Mold on travertine floor/through painter's fleece/abandoned buckets

The shock was great... our bathroom was used as a storage room for various paint buckets, etc. To protect the floor (natural stone/travertine), painter's fleece was laid out. Now we have cleared the room and, to our horror, found that mold had formed in some places. Due to the fleece and the buckets on top, residual moisture from the floor probably accumulated. Fortunately, the spots are not large and we have probably prevented worse damage. From now on, the painters will only use painter's paper.

Does anyone have an idea how to get rid of the stains?
Mold remover didn’t work at all. Best regards, Steffi.

Contact your stonemason.