This is a clip from a 1954 French comedy set in a Burlesque theater. It seems to have a following on YOUTUBE with the whole film posted by a Russian. (With Russian dubbing) The clip has a musical number where early 20th Century gentlemen peek though the keyhole at a lady undressing. In the 1950s the art director or costumer got the layers of clothing right for 1900, even in a sex comedy.
This clip is the G rated version.
This clip is the full musical number (about 3 minutes in the beginning) and should only be viewed by Europeans.