PARIS — The mountain of bold-faced names attached to the film “Paris je t’aime,” which premieres tonight in the “Un Certain Regard” competition at the Cannes Film Festival, could result in one very crowded movie poster. The unconventional movie is really an amalgamation of shorts from 20 top international directors — including Gus Van Sant, Joel and Ethan Coen, Walter Salles, Gérard Depardieu and Wes Craven ­— and stars the likes of Natalie Portman, Maggie Gyllenhaal, Marianne Faithfull, Steve Buscemi, Ludivine Sagnier, Nick Nolte, Emily Mortimer, Willem Dafoe and Catalina Sandino Moreno.

In their own trademark styles, the filmmakers portray a romantic encounter in each of the 20 arrondissements (districts) of Paris. The various segments are woven together to form a dramatic narrative. Portman, who plays an acting student, stars in Tom Tykwer’s short about the 10th arrondissement, Juliette Binoche appears in Nobuhiro Suwa’s take on the second and Gyllenhaal enacts Olivier Assayas’ interpretation of the third.

The segments were filmed in short bursts — two days of shooting, for example, to produce a five-minute portion of the finished product. “One had to find the rhythm quick,” says French actor Gaspard Ulliel, who stars in Van Sant’s take on the Marais neighborhood, which was shot in a store on Rue Veille du Temple. But the brevity of the pieces did not scare away the directors. “They were all very enthusiastic about this project,” says producer Claudie Ossard, who was also responsible for the hit “Amelie.” “And in those five minutes, it’s easy to recognize their signature styles.”

The film opens wide on French screens on June 21.