Many of the extras in the film were Satmar Hasidim, who would spontaneously offer prayers and blessings at appropriate points in movie scenes, even though those were not scripted.
The interior scenes in Brooklyn were shot in actual houses and an actual synagogue, not on stages. Many of the interior house scenes were shot in the Sunset Park area of Brooklyn, in empty houses without heat, during a very cold January 2008.
The term "holy roller" doesn't have a French equivalent or logical translation, so the film was released in France with the English title "Jewish Connection."
Sam calls his father "tateh," which is a Yiddish term of endearment for a father (akin to the English word "dad"). See also Ragtime (1981).