Where is it possible to get married ?
In France you can't choose where your wedding ceremony will take place. It must be at the city hall of the bride's or groom's residency (he/she must have been living here at least for 1 month).
In case of « mariage mixte », the ceremony can take place in France or abroad.
Is it possible to get married elsewhere than at the city hall ?
No. The only choice left is if the bride and groom don't live in the same city, then they can choose in which one the wedding will be celebrated.
Who can celebrate a wedding ?
A « officier d'état civil » : the mayor or one of his assistants.
Regarding the religious ceremony, you're free to do what you want and to go where you want. It has no official recognition (nothing legal or illegal, it's regarded as a personal choice) in France but it must take place AFTER the civil ceremony.
On what day is it possible to get married ?
A wedding ceremony can take place any day of the week between Monday and Saturday. It will be decided at the time you fill your « dossier ».
« Mariage mixte » and French nationality
Being married with someone French does not automatically gives right to the French nationality. You must fulfill a few requirements :
You must have been married for 4 years to start the process of « déclaration ». You must still be living with your husband or wife, and the French partner must still hold his/her French nationality.
If your wedding ceremony took place abroad, it must have been written on the « registres de l'état civil français ».
This « déclaration » must be sent to the « tribunal d'instance » of your city of residency. You must send it to the ambassy if you still live abroad.