wondering is it is Ok to leave luggage in minivan-Vaux and Fountainebleau during the day? We would be en route from Paris to another town. We could spend the night in Melun and check our bags with the front desk or leave in our room, if it was ready, but this gives us a longer drive the next day.
I won't validate that plan.
It is always risky to leave luggage in a car; a van where hiding it is harder, even more so. If you do take the risk then make sure you carry a bag like a messenger bag with your computers, phones, meds, and any other valuables you would really not want to lose. And make sure you don't access trunk space at the site and don't leave anything visible in the car if that is possible. I don't know if a minivan has any way to stow gear so it isn't visible.
only if you want to find out if any burglars are active that day in the parking lots.
Sorry, Elaine; I can't endorse this plan either. A group of 4 friends visited Fountainebleau en route to Paris two years ago, leaving their luggage in their van. When they returned, everything was gone. I'd make the longer drive rather than take the risk.
Marlene