Overhanging sitstart boulder. You sitstart and exit in orange n°16: La Voie Dure à Bras. It helpt my not to mantle up in the heel, but just to use it to hold my position and move my recht hand to the undercling. Easy steps to the top, but a bit sandy.
Rain sucks, but broken holds suck even more. Remember, never climb on wet rock in Fontainebleau.
The sandstone becomes brittle, and pulling on it will ruin classic problems. Drying it doesn't help, because it's still wet and weak inside.
All you can do is wait for better conditions.