Italian environmental activists on Friday stuck their hands on the glass protecting Sandro Botticelli's painting "Spring" in the Uffizi Galleries in Florence.
The museum said the glass, installed as a precautionary measure several years ago, left the masterpiece unharmed.
Together with the Florentine artist's other masterpiece, "Birth of Venus", the two iconic paintings, dating from the late 15th century, are among the museum's most popular works of art.
According to the Carabinieri police, two young women and a man, all Italian and having bought tickets, organised the demonstration in the Uffizi hall dedicated to the painter.
The activists sat on the floor and unfurled a banner that read "Last generation, no gas, no coal".
The glue was safely removed from the glass.