A 16th-century hairpin, thought to belong to the wife of Henry II of France, has been discovered in a communal toilet.

The antique was found down the pan at Fontainebleau Palace outside Paris and had conservators scratching their heads as to why it was not found in a more royal setting.

The pin is thought to belong to Catherine de Medici, who was queen consort of France from 1547 to 1559.

A design on the pin, which is 9cm (4 in) long, shows a pair of interlocking C's - standing for Catherine. Fontainbleau Palace's conservator Vincent Droguet said he noted a finish of white and green, Catherine's colours, when the grime was cleaned off the pin.

The discovery was made by conservators who dug around the old toilet as the surrounding area was prepared for restoration.

The find is a valuable one as Catherine was renowned for her lavish jewellery, yet the majority of it has been lost or stolen over the centuries.

However, Droguet said it was a mystery how the pin would end up in a communal toilet, which would have been used by all, rather than in her royal chambers.

He said: "What would Catherine de Medici be doing there? Maybe it was a lady-in-waiting who took it. Perhaps it was stolen and just fell in."