I want to rent a car from the future

Europpos, what are the mainstream car rental agencies in and around Paris (CDG or Rouen) and London (Gatwick and maybe London proper)? I’ve heard about Sixt and know Enterprise and the lot are over there. What are your go-to agencies? I need something for 7 passengers minimum, so Citroen Spacetourer or the Merc V class size.

Look how cute it is!