"Bienvenue chez les Ch'tis" (its title is based on a dialect word for northerners) looks certain this weekend to break a 41-year record held by the 1966 comedy "La Grande Vadrouille", according to the film's producers Pathe.
The U.S. melodrama "Titanic" still holds the absolute record in France, with more than 20 million viewers, but "Bienvenue chez les Ch'tis" has become a phenomenon for the local industry, which has often struggled to produce home-grown hits.
"It's astonishing. It's amazing. I can't believe that we are the number one film of all times," the film's director and star Danny Boon told TF1 television, anticipating the French record.
The film pokes fun at stereotypes about the damp and chilly north, a region blighted by high unemployment and industrial decline whose inhabitants are often stigmatised in the rest of France as a backward race of uncouth beer drinkers.
Made for a reported 11 million euros (8.6 million pounds) by Boon, a native of the region, it centres on the trials of a post office manager transferred from an idyllic southern town to exile in the distant region of Nord-Pas-de-Calais.
He faces bad weather, incomprehensible local accents and an unfamiliar diet of fried chips, beer and a pungent local cheese normally enjoyed dunked in coffee ("It mellows it," he is assured).
Inevitably, however, he learns to appreciate the loveable cast of eccentrics he encounters.
Inspired by Boon's observation that most French comedies are set either in Paris or the sunny south, "Bienvenue chez les Ch'tis" has transformed the dour image of the north, bringing flocks of tourists to the town of Bergues where it was made.
Wildly popular among "Ch'tis" themselves, the film has attracted audiences across the whole country and President Nicolas Sarkozy is reported to have asked for a special private screening in the Elysee Palace.
The prejudices that still exist against the region were underlined by a banner unrolled at a football match last weekend involving the northern club of Lens, reading "Paedophiles, unemployed and inbred, Bienvenue chez les Ch'tis".
But the flood of outraged comment and the massive police hunt for the opposition supporters behind the taunt has underlined the effect the film has had.
Germanyy to consider a possible remake based on regional differences in their own countries, a Pathe executive told Le Monde last month.
Its success has also inspired filmmakers in the United States and
"Bienvenue chez les Ch'tis" itself looks unlikely to be an international hit with much of its humour based on accents and dialect which inevitably get lost in translation.