The couple exchanged vows in front of a group of 11 family friends at the town hall in Mazan, near the city of Marseille, Hello! magazine reported.
Around 50 guests were expected to attend the evening reception which is being organised at the residence of the actress's mother nearby.
Not too many A-listers are likely to attend the party although her close actress friend Sienna Miller is rumoured to have joined in the celebrations.
The pair struck up a friendship after starring alongside each other in 2008 flick, The Edge of Love, written by Keira's mother.