With sadness and distress I've read (some) of the IMDb reviews on Le Fils de Jean. However, it shouldn't be surprising as most people are prone to blockbusters and sound bytes.
Although I wouldn't exactly describe this as the art of slow cinema, it nevertheless moves along with a gentle pace, portraying gentle emotions and the odd outburst or two. Primarily it's a film about relationships between parents and children, and vice versa and between siblings.
Very seldomly do French films hit the viewer over the head with melodramatic confrontations and every realisation and experience rushing along like car chases. Most of the time they allow the viewer to discover the characters and have rare looks into their inner beings. Although this is not particular or peculiar to French films, a general sense of melancholy and romance are ever subtly present in French works.
One reviewer in particular slates the acting. I can only presume that said person is not acquainted with the works of Ingmar Bergman, Andrei Tarkovsky, Theo Angelopoulos and most works from Europe. Even thrillers such as The Hunt (Thomas Vinterberg) are not shoved down viewers' throats with grandstanding.
The great French film masters (Robert Bresson, Agnes Varda et al) also, like thorough painters, take time to uncover their characters, their stories and their situations.
I won't compare Le Fils de Jean (directed by Philipe Lioret, also responsible for the wonderful Welcome starring Vincent Lindon) with any of the great masters' films, but it's a gem. Mathieu, who visits Canada to find out more about his (presumed dead) father Jean and is taken to the lake where he supposedly drowned, finds himself in a different world. Albeit all French speaking, even certain expressions and customs are foreign to him (and vice versa again).
This is not operatic, melodramatic, grand scale acting. This is gently coming to grips with the soul and marrow of every character. This is real. Sincere. Supported by excellent photography, the wonderful script is brought to life by director and actors and the film is strewn with small, delicate delights. And. a big AND, not everything is explained as in Hollywood films. The viewer can come to own conclusions. Mine were certainly being moved, being transported and being touched.
This is worth a few revisits.