French is the sole official language in France according to the second article of the French Constitution. French, a Gallo-Romance language, is spoken by nearly the entire population of France.

In addition to French, several regional languages are also spoken to varying degrees, such as Alsatian, an Alemannic variety; spoken by 1.44% of the national population); Basque, a language isolate; Breton, a Celtic language (spoken by 0.61%); Corsican, an Italo-Dalmatian language; and various other Gallo-Romance languages (Langues d'oïl 1.25%, Occitan 1.33%). Some of these languages are also spoken in neighbouring countries, such as Belgium, Germany, Switzerland, Italy, Andorra, or Spain.

The official language of the French Republic is French (art. 2 of the French Constitution) and the French government is, by law, compelled to communicate primarily in French. The government, furthermore, mandates that commercial advertising be available in French (though it can also use other languages). The French government, however, does not mandate the use of French by private individuals or corporations or in any other media.

A revision of the French constitution creating official recognition of regional languages was implemented by the Parliament in Congress at Versailles in July 2008.

The 1999 Report written for the government by Bernard Cerquiglini identified 75 languages that would qualify for recognition under the government's proposed ratification of the European Charter for Regional or Minority Languages. Of those languages, 24 are indigenous to the European territory of the state while all the others are from overseas areas of the French Republic (in the Caribbean, Indian Ocean, Pacific Ocean and South America).

Although ratification was blocked by the Constitutional Council as contradicting the Fifth Republic's constitutional provision enshrining French as the language of the Republic, the government continues to recognise regional and minority languages to a limited extent (i.e. without granting them official status) and the Délégation générale à la langue française has acquired the additional function of observing and studying the languages of France and has had et aux langues de France added to its title. The category of languages of France (in French: langues de France) is thus administratively recognised even if this does not go so far as to provide any official status. Following his election as president, François Hollande reasserted in 2012 his campaign platform to ratify the European Charter and ensure a clear legal framework for regional languages (within a programme of administrative decentralisation that would give competencies to the regions in language policy).

The regional languages of France are sometimes called patois, but this term (roughly meaning "dialects") is often considered derogatory. Patois is used to refer to essentially oral languages, even though some have a current and/or historical use, such as Occitan, which was already being written at a time when French was not and its literature has continued to thrive, with a Nobel Prize for Frédéric Mistral in 1904.

It is estimated that at the time of the French Revolution in 1789, only half of the population of France could speak French, and as late as 1871 only a quarter spoke French as their native language.