Third Army (GAN) on the northern flank of (GAR) had been reduced to the Third Army with three corps in line, by the transfer of the First Army to the GAR. The Third Army began French operations, with preliminary attacks on German observation points at St. Quentin on Large reconnaissance forces were sent towards the Dallon spur on 1 April, which were not able to gain footholds in the German front defences, although the British Fourth Army to the north captured the woods around Savy. On 2 April a bigger French attack on Dallon failed but on 3 April the Third Army attacked after a "terrific" bombardment, on a front of about north of a line from Castres to Essigny-le-Grand and Benay, between the Somme canal at Dallon, south-west of St Quentin and the Oise. After another attack on 4 April, the villages of Dallon, Giffecourt, Cerizy and côtes south of Urvillers, were captured and the German position at the apex of the triangle from Ham to St Quentin and La Fère was made vulnerable to a further attack. The French had attacked in intense cold and driving rain, with chronic supply shortages caused by the German destruction of roads and immense French traffic jams on the few supply routes which had been sufficiently repaired to bear traffic. East of the Oise and north of the Aisne, the Third Army took the southern and north-western outskirts of Laffaux and Vauxeny. On 4 April German counter-attacks north of the Aisne were repulsed south of Vauxeny and Laffaux. The French captured Moy on the west bank of the Oise, along with Urvillers and Grugies, a village opposite Dallon on the east bank of the Somme. North of the farm of La Folie, the Germans were pushed back; three howitzers and several lorries were captured. Beyond Dallon, French patrols entered the south-western suburb of St. Quentin. The main attack by GAN was planned as two successive operations, an attack by XIII Corps to capture Rocourt and Moulin de Tous Vents south-west of the city, to guard the flank of the principal attack by XIII Corps and XXXV Corps on Harly and Alaincourt, intended to capture the high ground east and south-east of St. Quentin. Success would enable the French to menace the flank of the German forces to the south, along the Oise to La Fère and the rear of the German positions south of the St. Gobain
massif, due to be attacked from the south by the Sixth Army of the GAR. The French were inhibited from firing on St. Quentin, which allowed the Germans unhampered observation from the cathedral and from factory chimneys and to site artillery in the suburbs, free from counter-battery fire. French attacks could only take place at night or during twilight and snow, rain, low clouds and fog made aircraft observation for the artillery impossible. German work on the (Hindenburg Line) continued but the first line, built along reverse-slopes was complete and from which flanking-fire could be brought to bear on any attack. Concrete machine-gun emplacements proved immune to all but the heaviest and most accurate howitzer-fire and the main position was protected by an observation line along the crest in front, which commanded no man's land, which was deep. The British Fourth Army was unable to assist the French with an attack due to a lack of divisions, after transfers north to the British Third Army but was able to assist with artillery-fire from the north and kept a cavalry division in readiness to join a pursuit. The French artillery had been reduced to guns by transfers south to GAR, which was insufficient to bombard the German defences and conduct counter-batter fire simultaneously. On 13 April at XIII Corps attacked with two divisions; the 26th Division on the right took the German first line and then defeated two German counter-attacks but the 25th Division on the left was held up almost immediately by uncut wire and machine-gun fire, despite French field artillery being advanced into no man's land at the last minute to cut the wire. Casualties in the thirteen attacking battalions were severe. The 25th Division was ordered by the army commander, General Humbert to attack again at but the orders arrived too late and the attack did not take place. French aircraft were active over the attack front but at midday large formations of German fighters arrived and forced the French artillery-observation and reconnaissance aircraft back behind the front line. By the end of the day the 26th Division had held on to of the German front trench and the 25th Division had been forced back to its jumping-off trenches. German artillery-fire had not been heavy and the defence had been based on machine-gun fire and rapid counter-attacks. The XIII Corps and XXXV Corps attack due next day was eventually cancelled.
Fifth and Sixth armies The Fifth Army attacked on 16 April at which had dawned misty and overcast. From the beginning, German machine-gunners were able to engage the French infantry and inflict many casualties, although German artillery-fire was far less destructive. Courcy on the right flank was captured by the 1st Brigade of the
Russian Expeditionary Force in France but the advance was stopped at the Aisne–Marne canal. The canal was crossed further north and Berméricourt was captured against a determined German defence. From Bermericourt to the Aisne the French attack was repulsed and south of the river French infantry were forced back to their start-line. On the north bank of the Aisne the French attack was more successful, the 42nd and 69th divisions reached the German second position between the Aisne and the Miette, the advance north of Berry penetrating . Tanks to accompany the French infantry to the third objective arrived late and the troops were too exhausted and reduced by casualties to follow them. Half of the tanks were knocked out in the German defences and then acted as pillboxes in advance of the French infantry, which helped to defeat a big German counter-attack. German infantry launched hasty counter-attacks along the front, recaptured Bermericourt and conducted organised counter-attacks where the French infantry had advanced the furthest. At Sapigneul in the XXXII Corps area, the
37th Division attack failed, which released German artillery in the area to fire in
enfilade into the flanks of the adjacent divisions, which had been able to advance and the guns were also able to engage the French tanks north of the Aisne. The defeat of the 37th Division restored the German defences between Loivre and Juvincourt. The left flank division of the XXXII Corps and the right division of the V Corps penetrated the German second position south of Juvincourt but French tanks attacking south of the Miette from advanced to disaster. German observers at Craonne, on the east end of the Chemin des Dames, were able to direct artillery-fire against the tanks and destroyed behind the French front line; few of the tanks reached the German defences and by the evening only ten tanks were operational. On the left flank, V Corps was stopped at the and the hamlet of . On the Chemin des Dames, I Corps made very little progress and by evening had advanced no further than the German support line, ahead. The French infantry had suffered many casualties and few of the leading divisions were capable of resuming the attack. The advance had failed to reach objectives which were to have fallen by but prisoners had been taken. The attack on the right flank of the Sixth Army, which faced north between Oulches and Missy, took place from Oulches to Soupir and had less success than the Fifth Army; the II Colonial Corps advanced for in the first thirty minutes and was then stopped. The XX Corps attack from Vendresse to the Oise–Aisne Canal had more success, the 153rd Division on the right flank reached the Chemin des Dames south of Courtecon after a second attack, managing an advance of . The VI Corps advanced its right flank west of the Oise–Aisne Canal but its left flank was held up. On the east-facing northern flank near Laffaux, I Colonial Corps was able to penetrate only a few hundred yards into the defences of the (Condé Switch trench) and failed to take Moisy Farm plateau. Laffaux was captured and then lost to a counter-attack before changing hands several times, until finally captured on 19 April. To the east of Vauxaillon, at the north end of the Sixth Army, was captured with the help of British heavy artillery but then lost to a German counter-attack. The Sixth Army operations took approximately 3,500 prisoners but no break-through had been achieved and the German second position had been reached at only one point. On the second day, Nivelle ordered the Fifth Army to attack north-eastwards, to reinforce success, believing that the Germans intended to hold the ground in front of the Sixth Army. The Fifth Army was not able substantially to advance on 17 April but the Sixth Army, which had continued to attack overnight, forced a German withdrawal from the area of Braye, Condé and Laffaux to the , which ran from Laffaux Mill to the Chemin des Dames and joined the original defences at Courtecon. The German retirement was carried out in a rush and many guns were left behind, along with
vast stocks of munitions. The French infantry reached the new German positions with an advance of .
Fourth Army On 17 April the Fourth Army on the left of (GAC) began the subsidiary attack in Champagne from Aubérive to the east of Reims which became known as , with the VIII, XVII and XII Corps on an front. The attack began at in cold rain alternating with snow showers. The right flank guard to the east of Suippes was established by the 24th Division and Aubérive on the east bank of the river and the 34th Division took and . The "Monts" were held against a German counter-attack on 19 April by the 5th, 6th ( divisions), the 23rd division and one regiment between Nauroy and Moronvilliers. On the west bank the Moroccan Division was repulsed on the right and captured on the left. To the north-east of the hill the advance reached a depth of and next day the advance was pressed beyond . The Fourth Army attacks took and German attacks on 27 May had temporary success before French counter-attacks recaptured the ground around ; lack of troops had forced the Germans into piecemeal attacks instead of a simultaneous attack along the whole front.
Tenth Army Nivelle ordered the Tenth Army forward between the Fifth and Sixth armies on 21 April. The IX Corps and XVIII Corps took over between Craonne and Hurtebise and local operations were continued on the fronts of the Fourth and Fifth armies with little success. An attack on Brimont on the capture of which would have been of great tactical value, was postponed on the orders of the French government and never took place. The Tenth Army captured the Californie Plateau on the Chemin des Dames, the Sixth Army captured the for along the Chemin des Dames and then advanced at the salient opposite Laffaux. An attack on 5 May southeast of Vauxaillon took Moisy Farm and Laffaux Mill and repulsed German counter-attacks. Next day another advance was conducted north of the mill. German counter-attacks continued in constant attack and counter-attack in the Soissons sector. By the end of 5 May the Sixth Army had reached the outskirts of Allemant and took roughly 4,000 prisoners. The offensive continued on the Fourth Army front where was captured and by 10 May and had been taken by the French armies.
German 7th Army counter-attacks Between Vauxaillon and Reims and on the Moronvilliers heights the French had captured much of the German defensive zone, despite the failure to break through and Army Group German Crown Prince counter-attacked before the French could consolidate, mostly by night towards the summits of the Chemin des Dames and the Moronvilliers massif. During the nights of the May, the Germans attacked from Vauxaillon to Craonne and on the night of German attacks were repulsed at Cerny, La Bovelle, Heutebise Farm and the Californie Plateau. Next day, German counter-attacks on Chevreux, north-east of Craonne at the foot of the east end of the Chemin des Dames were defeated. More attacks on the night of were defeated by the French artillery and machine-gun fire; the French managed to advance on the northern slopes of the Vauclerc Plateau. On 10 May, another German attack at Chevreux was defeated and the French advanced north of Sancy and on the night of and the following day, German attacks were repulsed on the Californie Plateau and at Cerny. On 16 May, a German counter-offensive, on a front of from the north-west of Laffaux Mill to the Soissons–Laon railway, was defeated and after dark more attacks north of Laffaux Mill and north-west of Braye-en-Laonnois also failed. French attacks on 17 May took ground east of Craonne and on 18 May, German attacks on the Californie Plateau and on the Chemin des Dames just west of the Oise–Aisne Canal, were repulsed. On 20 May, a counter-offensive to retake the French positions from Craonne to the east of Fort de la Malmaison, was mostly defeated by artillery-fire and where German infantry were able to advance through the French defensive barrages, French infantry easily forced them back; prisoners were taken. On 21 May, German surprise attacks on the Vauclerc Plateau failed and on the following evening, the French captured several of the remaining observation posts dominating the Ailette Valley and three German trench lines east of Chevreux. A German counter-attack on the Californie Plateau was smashed by artillery and infantry small-arms fire and taken.
Battle of the Observatories At on 23 May, a German assault on the Vauclerc Plateau was defeated and on 24 May, a renewed attack was driven back in confusion. During the night the French took the wood south-east of Chevreux and almost annihilated two German battalions. On 25 May, three German columns attacked a salient north-west of Bray-en-Laonnois and gained a footing in the French first trench, before being forced out by a counter-attack. On 26 May German attacks on salients east and west of Cerny were repulsed and from German attacks between Vauxaillon and Laffaux Mill broke down. Two attacks on 28 May at Hurtebise were defeated by French artillery-fire and on the night of and attacks by the Germans west of Cerny also failed. On the morning of 1 June, after a heavy bombardment, German troops captured several trenches north of Laffaux Mill and lost them to counter-attacks in the afternoon. On 2 June a bigger German attack began, after an intensive bombardment of the French front, from the north of Laffaux to the east of Berry-au-Bac. On the night of two German divisions made five attacks on the east, west and central parts of the Californie Plateau and the west end of the Vauclerc Plateau. The Germans attacked in waves, at certain points advancing shoulder-to-shoulder, supported by flame-thrower detachments and gained some ground on the Vauclerc Plateau, until French counter-attacks recovered the ground. Despite the French holding improvised defences and the huge volumes of German artillery-fire used to prepare attacks, the German organised counter-attacks () met with little success and at Chevreux north-east of Craonne, the French had even pushed further into the Laon Plain. ==Aftermath==