Des crimes presque parfaits S02 E01 Episode 1

On May 16, 1937, in Paris, at the end of the day, Laetitia Toureaux, a beautiful young woman of 29 years old, rides in the metro at Porte de Charenton station, head of line 8. She takes place, alone, aboard the first class wagon. Less than three minutes later, the travelers who go up to the next station discover his stabbed corpse. Passionate crime or political execution?