The film is also known as L'homme de la tour Eiffel in France.
Plot
In the streets of Paris a myopic knife grinder Heurtin is berated by his partner both for his lack of money and initiative. Nearby, Kirby, an idle, cash-strapped playboy, enters a restaurant to meet his wife. He is warned by the waiter that both wife and his mistress are waiting for him at the bar. The nature of her husband's relationship becomes obvious to the wife, who taunts the mistress Edna that Kirby will have no money until his aunt dies, then leaves. Kirby reads a note that has been left at his feet, revealing that his predicament has been overheard, and he can be helped for a million francs. He grasps it is an invitation to murder, signed "MV". As Edna leaves, Kirby says he has a decision to make and if he throws two aces with poker dice he'll say yes. All five come up aces.
In the darkness of the aunt's house Heurtin finds a woman dead. In a panic, he falls over, losing his makeshift eyeglasses. The figure of a man appears, his feet and hands wrapped to avoid leaving prints. He intentionally steps on the glasses, and Heurtin leaves the house in literal blind terror. Outside a mysterious accomplice reassures him and promises to protect him if he lays low.
The newspapers say that both the aunt and her maid were murdered. Inspector Maigret takes the case, and finding the broken glasses soon arrests Heurtin. In prison, Heurtin's partner apologises to him for her nagging, which she realises drove him to crime. Maigret suspects that Heurtin was guilty of burglary only but won't talk, so he arranges a bogus prison escape so he can be followed. Unfortunately, the scheme backfires and Heurtin eludes his tail. At a bar where he finds the Kirby trio, Maigret spots Heurtin, who is clearly looking for his accomplice. They leave, and when a patron there ostentatiously creates a row by ordering luxurious foods he cannot afford to pay for, the police are called; Maigret suspects it's an exhibition to frighten away Heurtin.
Legwork reveals that the diner, Johannes Radek, is a brilliant and educated young man suffering from manic depression. In his elevated state he taunts Maigret, setting off a game of cat and mouse. Frightened back to the scene of the crime by Radek, Kirby shoots himself after being identified by Maigret, but gives up the letters MV before dying. Redek then sets Mrs. Kirby and Edna against one-another in an effort to implicate them in the murders.
Finally, a clever ruse by Maigret sends a cornered Radek fleeing to the Eiffel Tower, which he begins to climb. Heurtin angrily follows him up. Radek prepares to dive spectacularly from near the top, but becomes crestfallen when Maigret feigns disinterest and starts descending in his elevator cart. Plunged into depression he must be assisted down.
Maigret meets Radek one last time at the guillotine, but declines to watch. In the street outside Maigret strolls amid young Parisian couples displaying their amour. He spots Heurtin with his partner, happily wearing proper spectacles. Cheered, Maigret returns to police headquarters.
