Here in Paris, the most common reaction to the topless photos that I've seen has been a typically French squint. They furrow their brow, raise one side of their mouth as if to show off a newly capped incisor, and exhale noisily. The English-speaking equivalent of the expression would be "duh". The subtext is, what did you expect? The second a famous woman takes off her bikini top anywhere in France, she is going to hear the click of a camera and the patter of tiny fingers emailing the photo to a magazine editor.