To get legally married in France one of you needs to have lived in France for the 40 days immediately before the wedding date. French authorities also require a number of documents to be translated by a sworn translator. Besides, only authorities at the local Mairie (Town Hall) can perform a legally binding ceremony according to French law.
No other form of religious or humanistic wedding is recognised by the French Government.
This applies also to French couples, who often get married at the Marie first and then go to have a second ceremony in a church, synagogue or other venue of choice.
Because of the complicated and limiting legal requirements, many foreign couples choose to get legally married in their home country and then have a symbolic wedding in France (or do the symbolic ceremony first and then get legally married at home – whichever works for them). This way they don’t have to worry about paperwork and can have exchange their wedding vows where and when it suits them.