The company "A.W. Faber" was renamed to "Faber-Castell" in 1896, after the death of Lothar von Faber but before the marriage of Ottilie von Faber and Alexander von Castell. In the movie this event took place in 1900.
When talking to his friends Alexander von Faber-Castell mentioned the German power in Marocco, obviously referring to the first Marocco Crisis of 1904. However the scene is set around 1901/1902.
After Wolfgang's death Ottilie said that she gave birth to another child, which would refer to her fourth child Irmgard, who was born in 1904. In a following scene Ottilies grandmother dies. However this took place in 1903.
Unlike in the movie Ottilie didn't inherited the pencil factory first, but rather the family foundation that is in charge of the family owned real-estate, which was not yet part of the factory. The factory was inherited by her grandmother Ottilie Sr.
Ottilie is lighting Lothar von Faber's cigar with a Zippo lighter, which was invented in the 1933, while the scene takes place in 1896.
When mentioning the German colonies in Africa Count Alexander von Castell mentioned "The Place at the Sun". This term, referring the the African colonies was first used by the German politician Count Bernhard von Bülow in 1897. The scene however takes place in 1895/1896.
According to sources about the family of Faber-Castell it is not proven that Ottilie von Faber-Castell was actually pushed of the responsibilities as the leader in the company, as shown in the movie.