When Maurice flicks the eight flowers at Suzanne, they end up scattered around her feet, as she stands in front of the chair. However, when Dr. Giraud is brought home from the ball by his wife and first sits down in the chair, the flowers are in a somewhat more concentrated area. Then, after Suzanne has berated her husband, the camera cuts back to the doctor, still seated, who is able to pick up all the flowers that are now in a very small area, directly at the doctor's feet.
When Suzanne has finished watching Maurice, she closes the blinds. Later, she accompanies Paul to the door as she sends him off to confront Maurice. She then returns to the window and closes the blinds again.
That Monsieur Lalle does not tell the police who he is shows a sensibility towards Madame Giraud -- if she were found alone with him by the police, it would place her in a terrible position. He does the gentlemanly thing to save her reputation. So this is not a plot hole.