Three oil paintings by the renowned 19th century French artist Paul Cezanne, valued at a total of about $3 million, were discovered stolen today from the Art Institute of Chicago, museum officials reported.

It was the second art theft from the museum in 10 days, and follow the Christmas Eve theft of a $1 million Rembrandt painting from the DeYoung Museum in San Francisco.

"We are deeply distressed by this terrible event," said E. Laurence Chalmers Jr., museum president."Cezanne is one of the most important painters in the history of art. If the paintings are not recovered, it will be tragic loss."

The three paintings, discovered missing from a locked storage room by a museum staffer, are: "Madame Cezanne in a Yellow Armchair" (1893-95), "Apples on a Tablecloth" (1886-1890), and "House on the River" (1885-1890).

The paintings, which were removed from their frames by one or more thieves, were kept in the storage area while a place was being prepared for them in the gallery.

The area is accessible only to a limited number of museum employes with special keys, museum officials said.

"We have no way of knowing if there is a connection" between the Cezanne theft and the missing Rembrandt in San Francisco, said FBI agent John Otto, who is investigating the theft along with city police.

"There's no indication there is a connection. In fact, there's no indication of a forced entry here."

Asked if the theft was an inside job, a museum spokeswoman replied: "Who knows?Someone could have taken the keys from an employe."

She said she did not know how many keys there were but "I doubt if there were more than 10."

On Dec. 17, an 18th century Japanese painting valued at $5,000 was taken from a gallery at the Art Institute. Museum officials declined to speculate if there was a connection with the Cezanne thefts.

J. Patrice Marandel, the Art Institute's curator of earlier painting, said the Cezanne paintings are extremely valuable and fragile.

"These are oil paintings on canvas and should bot be left outside in freezing weather," he said.

Cezanne is regarded as the father of modern art. The Art Institute has one of the world's most extensive collections of French Impressionist patintings.

The Rembrandt painting in San Francisco, entitled "Portrait of the Rabbi," was taken by a thief or thieves who dropped through a skylight at the museum on the night before Christmas. Three less valuable paintings also were stolen.

Cezzanne, born in Aix-en-Provence in 1839, was influenced at first by the early impressionists before gradually developing his own; independent style. That style combined the luminosity of impressionism with the stability and harmony of classical art.

The three stolen paintings were done in Cezanne's maturity, when he achieved his fullest mastery. Their value is determined by Cezanne's importance as the father and mentor of the modern art movement.

Art historians consider Cezanne the bridge from the old masters to the modernists.

"He is the prophet of all that has happened in art and architecture in the classic tradition in the lass three-quarters of a century," said James McLaughlin, curator of the Phillips Collection, which owns a number of Cezannes.

"Madame Cezanne in a Yellow Armchair" was called "one of the absolutely greatest and one of the most important paintings" in the collection by James M. Speyer, curator of 20th century art at the Chicago Art Institute.

"They are priceless. I don't think the money means a thing. There's no possible sense to them being stolen because they can never be sold. The obvious reason they're of importance is that they were done by one of the great artists of the world."