Climate activists from the “Last Generation” group caused damage of up to 12,000 euros in the Dresden Old Masters Picture Gallery in August.
This was reported by the "Sächsische Zeitung" on Thursday in its online edition.
The "Bild" newspaper had previously reported on it.
On August 23, a young woman and a young man glued themselves to the frame of Raphael's Sistine Madonna – the Dresden gallery's best-known work.
Later, paintings in other German cities were also affected.
In the meantime, the traces of glue have been completely removed by restorers from the Staatliche Kunstsammlungen Dresden (SKD).
“In two places, where the hands stuck, the patination was damaged.
It is intended that these defects will be repaired," it said.
The costs for this would probably amount to 3000 to 5000 euros.
"In addition, the closure of the Old Masters Picture Gallery caused us to lose 7,000 euros in income," SKD spokeswoman Anja Priewe was quoted as saying.
Legal steps have not yet been initiated, but both a criminal complaint and a civil lawsuit are in progress.
"Against the background of comparable actions in other European museums, the SKD had already taken increased security measures," emphasized Priewe.
It has long been forbidden to take bags, coats and jackets into the exhibition rooms.
In addition, more supervisory personnel were posted in the Sixtina room in the picture gallery.
"These measures will continue to be maintained and supported by increased controls and continuous awareness-raising among our supervisory staff."