C'est jeune et ça sait tout! (1974)

When Charles Lebrun learns that his boss' 17-year-old daughter is pregnant, he fears that his 16-year-old niece Joëlle from France, who's spending her vacation with them in Canada, might fall into the same trap. So he and his wife decide to give her the lecture of the birds and the bees - but it turns out that she's already well informed and gives them a lecture about simultaneous orgasms. She inspires the sexually-repressed couple to start experimenting with "modern" forms of sex.