Hi!
Now you can only get the RMI after having worked quite a time or if you are now employed in Italy and would qualify for Unemployement money in Italy.
If you do not benefit of an E106 ( which is only valid 2 years ) you will have a problem with the French Health insurance, because then you will have to prove the existence of a private Health Insurance contract, equivalent to the CMU de base which costs at least Euro 3500 a year for one person.
The stay in France ( depends if you are a EU native or not ) has ben considerably toughened last year.
Citoyens communautaires en France - Service-public.fr
Yours,
pomhorn
PS. If you had a PACS or were married, then that would change everything if your friend qualified for the French Health Insurance, because then you could tag on without extra costs.