During the dinner when Eiffel presents the idea of the project the minister, Adrienne drinks while resting her elbow on the table. From an etiquette perspective, this is considered bad manners, which is not in line with her education and upbringing. She indeed points out to Eiffel during a previous dinner (in her youth) not to use a knife to eat asparagus.
When Gustave and Adrienne kiss on the first floor of the tower being constructed, the sun is shown as setting to the right of the then-palace on top of Trocadero Hill, i.e. to the North-North-West of Paris, when it should rather be to the South-West.