Gaining a French citizenship is not something that is undertaken without a commitment to the country and to its culture. Several requirements must be met to gain French citizenship, and while marrying someone who is already a citizen can speed the process, you still must meet some basic requirements. If you reside in France already and intend to stay in the country, becoming a citizen can be beneficial as living in France as a foreigner can be a legal headache.
Reside in France as a legally documented foreigner with a visa for at least five years. This is one of the primary requirements for applying for citizenship, and you will need to document your residency. If you marry a French resident, the amount of time you must live in the country is reduced, however you must still have a valid visa and live there for a specific period of time--exactly how long will depend on your circumstances.
Maintain solid employment in France. Being a productive citizen is one factor that will be taken into account when you apply.
Speak French, if not fluently then well enough to be able to function on a daily basis without difficulty. You are not expected to sound like a native speaker, but you will have to pass an interview in French.
Be at least 18 years old.
Prove good characters and morals, with a clean criminal record with no offences as a French resident.
Fill out the application and provide a birth certificate, proof of residency, and evidence of your profession. These documents, along with all the other requirements listed above, will be examined and a determination made as to granting permanent citizenship. This process can take up to two years from the time of application.