It's hard to say otherwise. They were moderate left in the 80s when they were doing nationalizations and pro-worker reforms. They've embraced free market in the 90s which is arguably not very left-wing. Leaving aside same-sex marriage for a minute, Hollande's rule was well-known for social regressions for workers (Loi travail) and minorities (Déchéance de nationalité, taking 7 year-old children into police custody for thought crimes), and handouts for wealthy elites (CICE). That, and systematically continuing to destroy public services that Sarkozy already harmed. That can hardly be called left-wing in my book... unless you'd like to name left-wing policies introduced under Hollande?
Hollande?
Exemption for capital gains on investment property pushed from 15 to 30 years retention.
Repelled sarkozys state financing tuition for French schools abroad.
Many other examples that no self respecting right wing politician would promulgate.
Hollande was (is) socialist.