The works by Pablo Picasso, Henri Matisse, Claude Monet, Paul Gauguin, Lucian Freud and Meyer de Haan were taken from Rotterdam's Kunsthal museum.
Experts were unable to put a value on the haul last night, but the theft is one of the art world's most dramatic in recent years.
The stolen paintings were listed as Pablo Picasso's Tête d'Arlequin; Matisse's la Liseuse en Blanc et Jaune; Monet's Waterloo Bridge, London and Charing Cross Bridge, London; Gauguin's Femme devant une fenêtre ouverte, dite la Fiancée; de Haan's Autoportrait; and Freud's Woman with Eyes Closed.
Kunsthal, designed by Dutch architect Rem Koolhaas, does not have its own collection and exhibits different types of art, including photos, sculptures, design and fashion.
It had only just opened a new exhibition a few days ago to celebrate its 20th anniversary.
It had paintings by Picasso, Marcel Duchamp, Piet Mondriaan, Monet, Vincent van Gogh, Freud, and others showing examples of impressionism, expressionism, and other modern art movements.
More than 150 paintings on display in the exhibit came from the privately owned Triton Foundation collection, and many of the works are worth a million euros or more.