Well, weight for a Clio 182 is 1090kg, and then you multiply 0.737kg for every litre of fuel you have in your tank, and then add yourself. Then for other liquids like engine oil, break fluid and screen wash, I’d add 25kg max.
This is a good start and probably an accurate of a guess anyone could make. Or if you know of one, go to your local weigh bridge. Mine cost me £10 ago, and that’ll be spot on.
And how much it weighted?