Youth career Mollo began his football career with
Olympique de Marseille in 1996, who were at the time attempting to bounce back from the
bribery scandal the club had endured in the early 1990s. After spending nearly eight years in Marseille's youth system, Mollo had a one-year spell at local club
Aubagne FC before moving to the
principality-based side
Monaco.
Monaco Just before the end of the
06–07 season, Mollo and Monaco agreed to terms on a professional contract with the player signing for three years. Mollo was promoted to the first-team and handed the number 26 kit for the
2008–09 season. He made his professional debut on 18 October 2008 in a 1–2 loss to
OGC Nice appearing as a substitute. On 7 December 2009, Mollo signed his first professional contract with Monaco.
Krylia Sovetov Samara In the summer of 2015, he joined
Krylia Sovetov Samara in the
Russian Football Premier League on loan. On 29 August 2015, in his second game and first start for Krylia Sovetov he assisted on all three goals as his new club unexpectedly defeated the reigning champion
FC Zenit Saint Petersburg with a score of 3–1 in an away game. On 31 August 2016, he moved to Krylia Sovetov on a permanent basis.
Zenit St. Petersburg On 10 January 2017, he signed a 3.5-year contract with
Zenit Saint Petersburg on a €3 million transfer fee. Before the 2017–18 season, Zenit hired
Roberto Mancini as their new manager and Mollo was moved to the second-tier farm-club
FC Zenit-2 Saint Petersburg. On 26 July 2017, he brought attention on himself by showing the middle finger to Zenit Saint Petersburg fans when being substituted. On 30 August 2017, he was released from his Zenit contract by mutual consent.
Fulham On 31 August 2017, Mollo signed for championship side
Fulham, signing a two-year contract. On 30 January 2018, Fulham announced the mutual termination of Mollo's contract, after featuring just six times for the club during his five months, and failing to play a full 90 minutes once.
Return to Krylia Sovetov Samara On 6 September 2018, he returned to Russia, rejoining
Krylia Sovetov Samara on a one-year deal. He left Krylia Sovetov in January 2019.
Sochaux On 28 January 2019, he signed with
Sochaux until the end of the 2018–19 season.
Panathinaikos On 25 July 2019, Mollo joined
Panathinaikos on a two-year contract. In January 2020 he joined Ligue 2 side
US Orléans on loan for the rest of the season. He made six appearances while Orléans placed last in the league when the season was abandoned due to the
COVID-19 pandemic. On 23 October 2020, after 11 months he is again part of Panathinaikos' squad. Specifically, the French winger had played for last time on 24 November 2019 in a match against
Panetolikos, as a late substitution. After a quarrel with club's coach
Georgios Donis, before a
Super League Greece match with
Xanthi F.C. he was loaned out, to return in the summer of 2020, with ex- Panathinaikos coach
Dani Poyatos not counting on him.
Olympique Alès On 5 December 2024, Mollo signed with
Olympique Alès in the fifth-tier
Championnat National 3. ==Personal life==