The shooting of the film will take place mainly in the market of this Adriatic seaport in late afternoons or in the evenings, the local authorities reported on Tuesday.
The shooting started in Pula in late February and the crew will move to Rijeka next week to continue shooting the film on 19 March on several locations in the biggest Croatian seaport.
The film is a German Westside Filmproduktion Gmbh production.
As many as 70% members of the crew are Croatian professionals.
Rijeka Mayor Marko Filipović was quoted as saying that the city's architecture and picturesque locations provide excellent scenery for making films.
"Momo", also known as "The Grey Gentlemen" or "The Men in Grey", is a fantasy novel by Michael Ende, published in 1973.