We do not want to drive into Paris, does anyone know of a place I can leave my car for 3 days while we catch a train into Paris? The car has to be returned to Brussels or we will be charged a $$$$$ fee. We will be doing Versaille the day before Paris.
Any chance that you don't really need the rental car? Or can you get rid of it before you leave Belgium?
There is a lot in Versailles - it is 22,80 € per day.
https://www.urbispark.fr/parkings_et_voiries/ile_de_france/versailles/parc_reine_richaud
Vinci has lots all over and around Paris; you can identify spots and prices on their website; some are underground and relatively secure. We used one near Place d'Italia on a day trip to Paris from Burgundy to meet family for a day.
The $$$$ drop-off fee may be equalled by the €€€€€€ parking fee for three days . . .
Think first if you need a car anyway in Belgium too. If you only visit cities there what most do it makes no sense having one as public transport is way more effective and cheaper. Maybe you only need one for an occasional daytrip to Ypres for instance, so rent a car just for that particular day or a few days.
From almost any place in Belgium it is more easy, faster and cheaper taking the train to Paris and from there one to Versailles. But if you nevertheless have a strong preference using a car you can do what sometimes I do and park the (my own) car for free outside Paris near a RER railway station and take the train to the city centre. But I only do that for one day during daylight and there is no guarantee parking for more days nothing will happen with the car. But before going further what are your thoughts for the moment?