Pockets!There aren't more than two hundred genuine sinker pockets to be found in the whole forest. This boulder has half of them.(The rest are all on Vigipirate at Restant du long Rocher, so head there next if you like this one)
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.