This was the 8th of the 14 Olsen Gang comedies, which were immensely popular in parts of Europe. They depict life from the point of view of petty bourgeois criminals with higher aspirations. (See
ls075500400 for the full list.) Most people seem to agree that this film and the preceding one,
The Olsen Gang on the Track (1975), are the best two in the series. In my opinion, this one is so outstanding that it is clearly the better of the two, though I can see how railway lovers who aren't into classical music might consider the previous one better.
Danish films from the 1970s look very similar to French films from the same decade, and have a very similar lightness to them. I think this may be due to the influence of the works of Jacques Tati, such as the famous
My Uncle (1958). Unfortunately the Danish films are generally less well known in some major markets. If you love the classical French films such as
The Tall Blond Man with One Black Shoe (1972) (with Pierre Richard) or
The Wing or The Thigh? (1976) (with Louis de Funès), then you will likely love the similar Danish films such as
Martha (1967) or the Olsen Gang as well. (PS: In the time since I wrote this review, I watched
The Avengers (1961) for the first time. The famous classical seasons featuring Emma Peel also have a similar style and may be better known globally.)
Most Olsen Gang movies consist of a short pre-coup followed by a big heist. This one is special in that it actually features two ingenious coups. The visually stunning arrival of the caterer at the baron's picturesque castle (played by Vallø Castle) marks the beginning of the first coup. The second coup takes place in the Royal Theatre in Copenhagen and requires extensive rehearsals by the gang to prepare for one of the most outrageously funny criminal coups in cinema history, involving a jackhammer, an orchestra, and precise timing.