Since late January 2022, a new rule for joining the French Foreign Legion has been applied. A PCR test no older than 24 hours is required now to enter the recruting centers and begin the selection process. According to the recruiting officers of the Legion, this new rule applies for all candidates from all countries, regardless of the degree of risk of infection, even for vaccinated individuals and people who have recently recovered from Covid.
The new rule will be required until further notice. The rule limits the risks and allows the recruiters not to force the candidates into isolation. Be sure that you provide a PCR test (a printed certificate). Not an antigen test.
To learn more about the enlistment in the Foreign Legion, recruting centers, and the selection process, follow this link: Joining the French Foreign Legion