French director Nicolas Philibert's documentary "On the Adamant", about a floating day-care centre on the Seine in Paris, won the Berlin film festival's Golden Bear top prize on Saturday.
"On the Adamant", coming more than two decades after Philibert's acclaimed education documentary "To Be and To Have", is about a floating day-care centre for people with psychiatric problems on the Seine in Paris.
Thanking the jury, Philibert, who is 72 years old, said "the fact that documentary can be considered to be cinema in its own right touches me deeply".
"On the Adamant" offers an intimate glimpse into the lives of adults and their carers in the Parisian day-care centre, which puts an accent on offering them a creative outlet.
The film is "an attempt to overturn the image we have" of people with psychiatric problems, Philibert said.
"The clichés are deep-rooted. The film tries to unravel them. There is a long way to go."
The Hollywood Reporter magazine praised the film's "warmth and enthusiasm", calling it "a portrait of several individuals who, despite their noticeable disabilities, are capable of producing original and moving works of art".
French President Emmanuel Macron congratulated both Philibert and his subjects on the win, calling the film a "story of humanity and commitment".
There was further success for France as Philippe Garrel won the Silver Bear for best director for "The Plough", a drama about three siblings from a family of puppeteers coping with the death of their father.
Garrel dedicated the prize to his children and to French-Swiss director Jean-Luc Godard, "a great master for many of us", who died last September.