This Slip-Up occurs a few minutes into the movie, while Van Helsing is in Paris, pursuing Mr. Hyde. In the background we can see an incomplete Eiffel Tower with two levels already completed, and construction cranes visible on top. The film is based mainly in 1887 (the opening scene is the only exception, taking place in 1886). The second level of the Eiffel Tower was not added until late 1888. In the time frame the movie is based in, there was only about half a level completed, as construction began in 1887.