Jean and Julie meet again ten years after childhood. Jean has trouble recognizing the grown up girl. Julie is "promised" to Henri, a neighbor. Julie, scathing and capricious, provokes Henri and Jean.

A bittersweet drama covering 30 years in the lives of group of friends united by their devotion to the theatre, 30 Ans begins in Paris in 1974, when Aurelian, his girlfriend Barbara, and childhood friend Antoine form a theatre. Taking the plight of Pinochet's oppressed Chile as its cause, the theatre attracts the involvement of Jeanne, a young actress who immediately sparks the attentions of both Aurelian and Antoine. When Chilean dissident actor Luis is brought to the theatre by Barbara's diplomat father, Jeanne falls in love with him, and the two carry out an affair that ends when a sudden development causes Jeanne to disappear. 8 years later, Aurelian has a new girlfriend and is directing a travelling troupe, and Antoine is a high-priced image consultant who gets his old friend a gig at Dunkirk. Aurelian, deeply immersed in a mid-life crisis, still loves Jeanne, continuing to carry a picture of the enigmatic actress in his wallet and writing about her in his diary.

Maurice Hartmann, a Parisian academic, annoys his young mistress with his cynical and disillusioned words and the void of his existence. The proposal of one of his students upsets his life: the young Kiyoshi offers him to taste his assortment of sushi and sashimi. In front of the delighted face of his teacher, Kiyoshi proposes to him to set up a small business of takeaway sushi for busy Parisians. Enthusiastic, Maurice struggles to find funding, and the "Sushi Express" gets off to a great start. But, after a good start, the small business stagnates ...

In a somewhat deflated story of robbery and deception set against the rooftops and byways of Paris, a group of enterprising petty thieves take advantage of the dog days of August to burglarize vacated apartments. At this time of year, all Parisiens are on vacation elsewhere, and the city is invaded by tourists on vacation from their own cities. In this mass rearrangement of the European population, the thieves get away with their looting until they run into an architect who catches them in the act. But his morals are nothing to brag about, as he gets more involved in what they are doing and wants some of their take. He is also smitten with one of the down-and-out women the thieves have been supporting (Dominque Laffin). As in so many French dramas, these conflicting relationships are doomed to be resolved only by tragedy.