Although a number of automakers' ridesharing services utilize cars owned by said automaker, Croove cars are privately owned, with Mercedes and German financial company Allianz handling the backend. Users, both car owners and lessors, can use the service through the iOS app. In this case it's far more like Turo than it is like GM's Maven service.
Cars on Croove can't be more than 15 years old and must be in good working condition. Regarding that, there's a modicum of accountability with Croove, and Allianz offers supplementary insurance over the course of the lease. Lessors must also fill out a profile, be at least 21, and will have to complete a check-in and check-out procedure with every car. Lessors must pick up and return vehicles to designated drop-off points.
Right now, Mercedes is only offering Croove services in Munich. If there is enough interest, Mercedes hopes to expand the service to other German cities. Presumably, they may expand to other countries if Croove is popular enough. The service falls under Mercedes Benz's Connected, Autonomous, Shared and Electric (CASE) corporate strategy. This includes vehicles like the upcoming, all-electric Mercedes-Benz EQ.