The actresses only read the script once. Abdellatif Kechiche insisted that they forget what the script said line for line, and instead asked them to improvise their scenes and really let their actions and words come out naturally and as unforced as possible.
There was controversy surrounding Abdellatif Kechiche and his work methods. It was revealed that he would do hundreds of takes for small scenes to achieve the desired realism of the story, and his intense directorial style was borderline abusive. Both actresses stated that the film looks so real because Kechiche pushed them to their breaking point, and that they were really struggling. They also said that they did not wish to work with him again. Stanley Kubrick has been accused of similar abusive working styles.
One of the sex scenes took 10 days to film.
There was no makeup artist and hairstylist on the set. The actresses were not allowed to wear makeup for most part of the movie.
For the first time ever the Palme d'Or at Cannes was also officially awarded to two of the actors. Usually only the director gets the distinction.