PARIS—Christie’s kickoff to its December 1 Impressioniste + Moderne auction in Paris is a fascinating array of Surrealist, modern, and postwar artworks that can truly be termed unique. Estimated at between €4 million and €6 million ($6–9 million), the Lefebvre-Foinet collection of more than 140 paintings, drawings, and sculptures by such artists as Alberto Giacometti, Max Ernst, Fernand Leger, Henri Matisse, Balthus, Victor Brauner, Matta, Jean-Paul Riopelle, Joan Mitchell, and Zao Wou-Ki was amassed by five generations of the family whose Left Bank shop furnished these artists with brushes, canvases, and paper, but most of all their famous tubes of colors and paints made from hand-ground natural pigments.

Paul Foinet founded the business in the 1880s, marketing his traditional artisan-made products by door-to-door visits to artist’s studios. In 1902, Foinet’s son-in-law, Lucien Lefebvre, opened the Montparnase premises on rue Bréa, called Lefebvre-Foinet, that would serve the art establishment for the next 90 years. Lucien was succeeded by his son, Maurice, a renowned figure, and then by Maurice’s daughter, Josette. Even after the Paris shop was closed in the mid-1990s, Lefebvre-Foinet honored a commitment to continue to make tubes and colors for about a dozen artists.

“It was extremely difficult and costly to do. The raw materials were hard to find; mines had stopped producing. Most paint pigments now are chemically manufactured,” explains Thomas Seydoux, Christie’s international director of Impressionism and modern art. “To keep the company afloat, they began selling about a picture a year. That’s how I got to know them.”

Following Josette’s death earlier this year, the heirs have decided to sell the collection. “The works that their parents and grandparents were given by the artists whom they themselves knew when they were children were never about value,” Seydoux confirms. “But they realize the collection has become quite valuable today. Their take is that they are not collectors, nor artists, but were working for artists. They are not familiar with the current art market at all, and the estimates [ranging from €1,000 to €1 million] are quite reasonable.”

Standouts include Alberto Giacometti’s oil portrait of Maurice Lefebvre, estimated at €700,000 to €1 million (or $1,049,683 to $1,499,548), painted in 1964–65. The artist kept it until his death but bequeathed it to Lefebvre, who reduced it slightly and re-stretched it into the current format in 1969. Seydoux also cites the “fantastic Alberto Magnelli works” like Lyrical Explosion C, a 1918–19 oil (est. $210–270,000) that vibrates with form and color, representing a turning point in 20th-century Italian art. Others include Sonia Delaunay’s vivid oil, Colored Rhythms No. 615 (finished between 1947–58, est. $110–160,000); a clutch of early Mattas (estimated between $21,000 and almost $300,000); Chinese painter Zao Wou-Ki’s brown, gray, and white-toned oil 5.11.64 from 1964 ($449,864–$599,819), which Josette hung in her living room, and a blue-hued Max Ernst oil from 1960, 33 Magi, Their Wives and Their Children ($81,000–$110,000) that she kept in her bedroom.

Along with art supplies, the Lefebvre-Foinets dispensed friendship, encouragement, advice, and often credit to indigent painters. American painter Dorothea Tanning (a.k.a. Mrs. Max Ernst) wrote in her autobiography of Monsieur Maurice’s “joviality towards gentlemen and gallantry in regard to ladies.” Many of the works were gifts and have personal dedications that provide a rare insight into the convivial lifestyle of the art world in 20th-century Montparnasse.

The family most esteemed a 1927 oil on canvas by Matisse, an unusual angular Seated Nude ($410–530,000) that long graced Maurice’s living room, the scene of his annual Christmas and New Year’s parties. Artist friends would arrive, often with works in hand. These gifts range from American Abstract Expressionist Joan Mitchell’s untitled 1959 clouds of colors ($410–530,000), inscribed “A Maurice With Love Joan,” to mini-pictures such Victor Brauner’s Untitled (Characters) ($11,000–$16,000) inscribed with holiday wishes to Josette on Jan. 1, 1950, and brightly painted with whimsical figures in watercolor and gouache on a torn piece of paper.