The Titanic arrived in Cherbourg, France in the evening, not daytime. And she didn't dock so passengers couldn't have boarded by gangway; she anchored in the harbor and passengers boarded tenders which traveled to her.
Adèle, living in Paris in 1911, has shaved armpits, but fashion didn't even start to introduce this trend until 1915.
Near the opening scenes, immediately after the can-can scene, when Mr Ferdinand Choupard arrives in front of the Jeanne D'Arc monument, the speaker says he's in the "place des pyramides" but it appears the place got this name only in 5 January 1932: in 1911, at the time when the story goes, its name was still "place de Rivoli".
When Adèle arrives at Paris station, one can see "SNCF" on one of the train cars. SNCF was created in 1938 but the movie is set in 1911.
The book, "Le Monstre des glaces" that Adele signs for Andrej, is a paperback book with a glossy colour card cover. Books were not printed in that style until at least the 1930s. There were, however, "penny dreadfuls" and "yellowbacks" published in Europe as early as the 1880s that did have color paperback covers though not on heavy card stock.