Sexy Boom(1974)

Madame Arrieu is the owner of an apartment building in Paris, where she lives with her three respectful nieces. Then, Elvira, a lady who paints nudes, gets behind in her lodging payments. Elvira, wishing to impress a prospective customer from the United States, asks Mme. Arrieu to let her use her (better) apartment, to receive him - just for a couple of hours. The lady refuses, but then she must leave for a short spell... Temptation is too big.