Diplomas in French as a foreign language are valid for lifetime.

The "DELF" and "DALF"

The DELF (basic diploma in the French language) and DALF (advanced diploma) are granted by the French Ministry of National Education. 

The DELF and DALF curricula are broken down into six separate levels, each of which corresponds to a specific degree of proficiency. The DELF is awarded to candidates who pass the first four levels. Candidates who go on to complete the last two levels are awarded the DALF.