My neighbour bequeathed several real estate properties to me in his will. I only wish to keep some of them. Is this possible?

Yes, provided that a legal heir (as defined by law) accepts the succession. In that case, you may exercise the right of cantonnement, which allows a legatee to limit their acceptance to part of the assets bequeathed. This is permitted under Article 1002-1 of the French Civil Code.