The Dutch-Spanish film emerged victorious in the main competition, Making Way, landing Lamberti the Kraków Film Award, worth USD 25,000, Poland's PAP news agency reported.
The prize was granted by an international jury led by the Polish filmmaker Tomasz Wasilewski. He was accompanied by British production designer Gemma Jackson and US producer Lee Magiday.
Meanwhile, Amatorzy (Amateurs), a movie by Iwona Siekierzyńska, scooped the award for best Polish feature film.
This PLN 100,000 prize, funded by Dominika Kulczyk Productions, was also awarded by an international panel of judges, headed by UK casting director Fiona Weir.
Lauded for its universality, Amatorzy tells the story of an amateur troupe of actors with intellectual disabilities, who unexpectedly win a theatre festival.
Best-acting prizes went to Poland's Agata Buzek and Jacek Braciak, who both shone in Moje wspaniałe życie (My Wonderful Life), while Nicolas Przygoda was named Mastercard Rising Star.
The international critics' federation, FIPRESCI, granted its award to Gaza mon amour, a film by Mohammad Abu Nasser and Ahmed Abu Nasser.
Meanwhile, the audience prize went to Najmro by Mateusz Rakowicz.
All the winners were announced at a closing gala on Saturday, as the festival director, Szymon Miszczak, thanked the 300 guests from Poland and abroad "whose energy and conversations made the event happen."
This 14th Mastercard Off Camera festival featured 80 movies from 25 countries, shown on eight screens around Kraków, thanks in part to the enormous work by 200 volunteers, the PAP news agency reported.