The version of the film screened at the Cannes Film Festival in May 2024 had 166 minutes of runtime. The version released in theaters in October 2024 had 161 minutes. Gilles Lellouche said he kept editing the film up until the weekend before its theatrical release and cut 3 scenes out - the dance sequence at the end of the film and the scenes that showed adult Clotaire being violent and trashing Jackie's house while begging to talk to her.
With a production budget estimated in EUR35,7 million, this is StudioCanal's biggest investment ever in a French-language film, and also the second most expensive French film of 2024, behind Le Comte de Monte-Cristo (2024) with a EUR43 million budget.
Despite the film's entire marketing focusing on François Civil and Adèle Exarchopoulos, they only shared a few scenes together and spent a total of 5 days shooting those scenes.
'Beating Hearts' was the lowest-rated film in the main competition at the 2024 Cannes Film Festival by both French and international critics, who complained about the film being too long, full of cliches, racist, misogynistic, that it ripped off several classic American films, that the love story wasn't credible, and that the two lead actors had no chemistry and were outshined by the two teenagers who played the younger versions of their respective characters. Critics and the audience also complained about this film being in main competition when there were better films out of competition or in sidebars at the festival that year. Screen International's Cannes jury grid gave the film a score of 1.4 out of 4 stars, while Chaos Reign's Cannes jury grid gave the film a score of 0.9 out of 4 stars, and Ioncinema's jury grid gave it a score of 1.6 out of 5 stars. Metacritic also included this film on its list of worst films from the 2024 Cannes Film Festival.
Director Gilles Lellouche said in several interviews between 2023 and 2024 that this film would have at least 3 hours of runtime. However, in the beginning of May 2024, the website of the Cannes Film Festival listed the film's runtime as 2 hours and 46 minutes, making it the second-longest film in official competition at Cannes 2024, behind Les graines du figuier sauvage (2024). Lellouche later said that the film's original version was 4 hours long.