Police carried out an operation Wednesday at the archaeology museum of Saint-Raphael on the French Riviera. A security perimeter had been set up around the building.
Police said the man was not armed. His motives were unknown.
French media say he allegedly broke out in the museum overnight and refused to communicate with police. They say the museum's cleaning woman alerted police when she arrived before the museum's opening.
Authorities said potentially threatening inscriptions in Arabic - for which the exact translation was unclear- were written on the building's wall.
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