The movie was initially supposed to be called 'Été 84' ('Summer of 84'). Robert Smith, the singer of The Cure, refused to grant François Ozon the permission to use his song The Cure: In Between Days (1985) because it was actually released a year later, in 1985. Ozon wrote back a letter to Robert Smith asking for a lower price for the rights and saying that he could change the name of his movie to 'Été 85', which was finally done.
At 49:51, The dress that David shows to Alex(is) is the dress that Lucia gave to Luc in Une robe d'été (1996), an early short film by François Ozon
Festival de Cannes - Official Selection 2020 (The regulars).
Quotation by Paul Verlaine in 'Romances sans paroles': "Il faut, voyez vous, nous pardonner les choses."
The film is based on the book "Dance on my grave" by Aidan Chambers.