Continuity mistake: In the scene at Le Grand Colbert restaurant in France the white rose in the vase on the table varies between a state of full bloom and being a small closed bud from shot to shot.
Continuity mistake: When Harry and Erica are having a picnic at the beach the sun light changes from shot to shot.
Deliberate mistake: When Harry is seen stepping outside of his hotel the evening after he arrives in Paris, behind him is the familiar Eiffel Tower gloriously illuminated against the night sky. Frequent Paris visitors or residents might recognise the hotel as the Plaza Athenee - to see the Eiffel Tower from there you'd need to be looking in the opposite direction from what we're shown.
Factual error: The audition scene for Erica's play would never take place in the theatre. Auditions and rehearsals are held in rehearsal halls, not the theatre. Yet they show the sets already built and installed, lighting and effects in place, and they reference the costumes being ready. This does not happen until the show is close to opening.
Continuity mistake: When Harry and Erica go to "sleep" together, they're on particular sides of the bed. The next morning, they're on opposite sides of the bed when they wake up.
Other mistake: When Erica and Harry are walking along the beach, picking up stones, and then Erica checks her watch because of her upcoming Dinner Date, she's not wearing her glasses, which she seems to need every other time she needs to look at the clock later in the movie.
Continuity mistake: When Harry and Erica lay in bed to "sleep" together, they are each sleeping in certain sides of the bed. The next morning, they've switched places in the bed.
Continuity mistake: When Tanya walks out of the kitchen with the Tylenol, there is a paper bag on the counter with the top folded in and the handles are not visible. When Amanda walks in 15 seconds later, the bag is now straight and the handles are visible. (00:27:30)
Continuity mistake: When Harry walks into the room carrying a photo album, there is a book with a photograph lying on it next to the dish of colored rocks. In the next shot, the photo has moved from the center of the book over to the edge next to the rocks. (00:44:00)
Continuity mistake: When Erika and Julian are talking in the kitchen "How are you holding up? - Me? - You." she makes a cup of tea and places the tea kettle on the stove. In the next couple of shots, the kettle moves from the right side to the left side of the burner. (00:35:55)
Continuity mistake: When Harry gets into the bed there are no eye glasses on the table on the left side of the bed. After they have slept for 8 hours and Harry and Erika have changed places the eyeglasses magically appear on the table. (01:09:35 - 01:10:15)
Continuity mistake: When a plate comes suddenly crashing to the ground, Erica is seen standing in her kitchen, above a white plate with a few bits of leftovers on that cracked plate. She is arguing with her sister about the "appropriateness" of the relationship between Harry and her daughter. As she bends down to pick it up, the plate is suddenly filled with red tomatoes and a heap of leftovers.
Answer: When they were trying to see what time it was the morning after they had slept together.