Hi!

If he is independant, he will have to register.
Registering imply high ( in relation to first turnover level ) URSSAF contributions. ( There can be changes he in the next year ).

See here ( nothing really on the contributions )

Comment opter pour le régime micro ou régime réel ?

He should contact the local: Chambre des Métiers, who should be able to help him to decide what to do.

It may be a good idea to work in a garage for some time, to get to know some of the ropes.

Yours,

giantpanda