Would Paris and Marseilles ident me on radar? Would they be able to inform me of restricted areas being active etc? Will they hand me over?
Most FIS sectors are radar equipped but do not provide a radar service as such. Sometimes you will be formally 'radar identified' other times it is only when they call specific traffic that you realise they are watching.
Remember to fly semi-circular headings (not quadrantal) and advise FISO of altitude changes.
I have flown your proposed route quite a few times now, usually skirting the Paris TMA just east of Soissons. The only issue I have ever had is transiting Lyon. The options are to follow the published low level route via Lyon Bron (at about 1500ft agl) or stay East or West of the TMA which is fine in good VMC but challenging in poor vis due to terrain.