Caroline Brandt is asking Carl Maria von Weber why he is not writing an opera about the own forest, the own people, meaning a story set in Germany and not in the Oriental regions, to which Weber is excited. However in real life von Weber already wrote various operas that were set in a German or Central European region, like "Silvana" from 1810 about a mountain forest Germany, "Peter Schmoll and his neighbors" from 1802 about Germany who try to build a new life in the Netherlands after the war, "Rübezahl" from 1805, based on the German legend of the same name etc.
Teresa Brunetti is portrayed as a young single woman, while in real life she was older and mature than Carl Maria von Weber, was married and had 5 kids and saw him as her young lover. In the movie however Eliza Illiard, who plays Brunetti, is 8 years younger than Willi Domgraf-Fassbaender, who plays Weber.
Carl Maria von Weber arrived in Prague on the 12th January 1813, while in the movie it resembles late spring.
Carl Maria von Weber and Caroline Brandt met in Frankfurt in 1810, not in Prague in 1813/14. Brandt even starred in von Weber's opera "Silvana". Also it was von Weber himself who hired her at the "Estates Theatre" in Prague.
Carl Maria von Weber started working in "Der Freischütz" in 1817 in Dresden, not in Prague. Also the official premiere was in 1821 in Berlin, while in the movie von Weber is already publicly conducting pieces from this opera in 1818, while the audience recognizes it.
While being in Prague Carl Maria von Weber is playing "Invitation To The Dance", which was written in 1819, while his time in Prague was 1813-1816.
Caroline Brandt is singing the adaption of "Wenn ich ein Vöglein wär" in 1814. However the tune that was used is by Carl Maria von Weber from the collection "7 folksongs, Op. 54" that was written and released in 1817.
When standing at the Calvary statue at the Charles Bridge in Prague, the two statues of Virgin Mary and Saint John are visible. Those were added to the Jesus statue only in 1861, while Carl Maria von Weber arrived in Prague in 1813.