The film does not have a traditional plot with twists, but the structural 'climax' occurs at the Royal Garden Restaurant. The newly opened venue literally falls apart due to shoddy construction. A ceiling decoration collapses, the AC malfunctions, and the glass door shatters.
This destruction acts as a catalyst: the social barriers dissolve along with the architectural ones. The stuffy, rich patrons begin to mingle with the rowdy Americans and the staff. Hulot meets Barbara, and a drunk American businessman creates a 'bistro' atmosphere in a ruined corner.
Ending: The next morning, the chaos subsides. Hulot buys Barbara a scarf and a pin (resembling the street lamps of old Paris) as a souvenir. He is unable to give it to her directly due to a crowd, so he passes it through a chain of people. As Barbara's bus leaves for the airport, the traffic circle around her transforms visually into a merry-go-round, implying that the cold, grey city has been imbued with the warmth of the previous night's 'play'.