You say "transferring MR". If you mean MRS Marseilles, there are two differences.
MRS has more flights to ORY than to CDG.
If you are in business, CDG has J to MRS, meaning middle seat empty. ORY does not (although middle seat might be left empty..

Seats should be the same, although AF is starting in September a new J seat with the major difference being a door. Only from CDG, not ORY. But there are only few planes already equipped (maybe one or two).