Changing sides to support
Talleyrand on 10 April 1814, Sébastiani was appointed to the
Bourbon Restoration Government and was, on 2 June, awarded the
Order of Saint Louis by
King Louis XVIII. Nevertheless, upon news that Napoleon was returning from
Elba, he abandoned his command and left for Paris, where, together with the
Count de Lavalette, he organized
National Guard detachments to assist the
Emperor. Napoleon also sent him over to attract support from the
liberal politician
Benjamin Constant; soon after, Constant became involved in drafting the more permissive
Acte Additionel, which amended the
Constitution of the Year XII. During the
Hundred Days, he was assigned the reviewing of legislation passed by Louis XVIII, and organized the National Guard in
Picardy. Sébastiani was elected to the
Chamber for the
department of
Aisne. After the
Battle of Waterloo, he voted in favor of Napoleon's
abdication, and, eventually, was among those assigned with negotiating a peace with the
Seventh Coalition (as part of a delegation also comprising
Benjamin Constant de Rebecque, the
marquis de La Fayette,
marquis d'Argenson and
comte de Pontécoulant). During talks, he showed himself opposed to a second
Bourbon return. Sébastiani spent a year in England before being allowed to return (having retired from active service and receiving half pay). Starting in 1819, after being promoted by the
Duke Decazes, he was a prominent member of the
Chamber of Deputies, initially representing Corsica, rallying with the
Left. According to the
Revue comments, his political choice was unusual, reportedly astonishing both members of the Left and the moderate Decazes, a Royalist. Inside the Chamber, he joined forces with
Maximilien Sebastien Foy, notably pushing projects to recognize the merits of
Grande Armée veterans; a speech he held on the latter occasion, which gave praise to the
French tricolor, caused an uproar among
conservative deputies. During the
1824 French legislative election, his attempt to campaign in
Corsica was frustrated by the local authorities representing the Royalist Government of
Jean-Baptiste de Villèle, and he subsequently won 1 out of 48 votes. Instead, after General Foy's death in late 1825, he was elected as replacement in his constituency, the
Aisne town of
Vervins, receiving 120 votes out of 200. ==July Revolution and Belgian question==