The Eiffel Tower: Public Domain by Day, Protected by Night

The tower went up in 1889; its copyright expired long ago. By day, anyone can photograph it and use the image commercially, no license required. At night, the rules change: the tower's illumination, installed in 1985, is treated as a separate artistic work under French copyright law - and that work is still protected. As such, commercial use of the tower's nighttime image requires authorization from the tower's operating company.

One monument, two sets of rules. And that lesson travels well beyond Paris: the question is never simply "is this protected?" It's "which layers are protected, who owns each one, and which rights do I need to clear?"