Sell a car to strangers on installments.

Good evening together have a question for you, maybe someone can help me further… And this is the following: I want to sell my car to a colleague from work, for 1500€ he can not pay the sum but once because he is only a temporary worker. His proposal he gives me half this month so 750€ and the rest next month. Unfortunately I don’t know him so well that I say ok no topic, not that he says then on the car is something rough and then I stand without Pap So my idea is to keep the car letter part 2 until he has paid me the full amount. Is that possible then the car belongs to me purely legally…. Is that possible at all? That he can register it and then everything? Unfortunately, don’t know about it at all… Would you be very grateful if any of you could help me!! Greeting Freddy