A portrait of an anonymous gentleman by the 17th-century Spanish painter Bartolome Esteban Murillo, bought by the Louvre in Paris in 1985 for $850,000, is at the center of a scandal over a stolen inheritance.

The affair involves a deranged millionairess and her collection of 15 old master paintings, a former barmaid who allegedly swindled her out of them, two of France's most eminent lawyers - and, of course, the Louvre. Authorities are investigating the scam, with repercussions that reach as high as the French culture minister.The millionairess, Suzanne de la Lombardiere de Canson, died at age 79 in September 1986 after spending the last months of her life a prisoner in the Toulon home of former barmaid Joelle Pesnel, 40. Pesnel and a lawyer friend, Robert Boissonnet, have both been charged with "theft, fraud, forgery and neglect of a person in danger"' after allegedly defrauding de Canson of her fortune in art works by using letters of procuration signed under duress.

De Canson's collection also included works by Van Dyke, de la Tour, Titian, Watteau, Boucher, Rembrandt and Guardi.

The Louvre, which had examined the paintings 15 years earlier, had details on file about the Murillo. Authorities now want to know how Louvre curators came to be satisfied with Pesnel's claims to ownership.

Pesnel spent half of the 5 million francs which the Louvre paid to a Swiss bank account. The whereabouts of all but three of de Canson's paintings are still unknown.

- THE MARK MORRIS COMPANY was a big success in its debut at its new home in Brussels' Theatre de la Monnaie last month. Morris's debut work was Handel's "L'Allegro, il Penseroso ed il Moderato" (based on poems by Milton), for which he hired an 11 extra Belgian dancers to supplement his own company of 15.

The audience applauded wildly, despite the fact that Morris had frankly disdained Maurice Bejart, his much-loved predecessor, who spent 27 years at the Monnaie and is considered to be the father of modern Belgian dance. "I have nothing in common with him (Bejart). I don't like his work and our approaches are totally different," Morris has said.

Morris, 32 - considered by American critics to be the world's best young choreographer - brought his company to Brussels in September on a three-year contract, to replace Bejart, who left for Switzerland after an argument with the Monnaie's director.

- STRINGS IN THE NEWS: In London, Timothy Hugh ended a performance with a flourish of splintering wood when he flung his cello to the ground and jumped on it. Along with other string players in the BBC Symphony Orchestra, the principal cellist was unhappy during rehearsals for an avant-garde piano concerto by German composer Helmut Flammer.

The musicians feared that the composer's instructions to bang the fingerboards and scrub up and down with their bows would damage their instruments.

In an unscripted finale, Hugh took revenge on a substitute cello, provoking a chorus of boos for the composer from fellow players. The scene caused uproar in the audience of about 100 contemporary music enthusiasts. Some of them thought the cello-smashing was part of the score.

In Houston, a Stradivarius violin reportedly insured for $2.5 million was stolen during a household burglary. The thief might not have known the violin's value. Stradivarius made more than 1,000 violins, violas and cellos, with about 600 known to be in existence.

And in London, a Guarneri violin sold at Sotheby's auction house for a record $1.05 million, breaking their previous record of $870,000 last March for a Stradivarius violin. About 150 Guarneri string instruments are believed to be still in existence.

- DANCE NOTES: The Kirov Ballet will dance in New York City next summer for the first time in a quarter century. A three-week engagement at the Metropolitan Opera House will begin on July 3 . . . Tim Wengerd, former Martha Graham principal dancer (also once with Salt Lake's Repertory Dance Theatre) has moved to Albuquerque. His new group, Tim Wengerd & Dancers had a studio showing in August, and he has a school, the Wengerd Conservatory, formerly the New Mexico Metropolitan Ballet School.

Ted Kivitt, former director of the Milwaukee Ballet, has been named artistic director of the NorthWest Ballet of Minneapolis. He heads the group that remains there following the failure of a proposed merger with Seattle's Pacific Northwest Ballet . . . Charles Reinhart and Martha Meyers celebrated their 20th anniversary as heads of the American Dance Festival last summer. . . Cincinnati/New Orleans City Ballet has added Knoxville, Tenn. to its permanent residency program, and will stage eight major performances there annually . . . Though nearing 67, Cuban ballerina Alicia Alonso recently danced "Giselle" in Havana, amid complaints that she should now stop dancing. She has danced for many years despite encroaching blindness.

- COMPOSER CHRISTOPHER ROUSE of Fairport, N.Y. won first prize and $5,000 in the 11th annual Kennedy Center Friedheim Awards, and orchestral competition for American composers. His winning work, Symphony No. 1, was commissioned by and performed by the Baltimore Symphony. Other winners in numerical order were George Rochberg, Stephen Paulus and Joan Tower.

- THE BOSTON BALLET and the Soviet Union's Kirov Ballet are working on an unprecedented joint production of "Swan Lake," for Boston in spring 1990, involving joint effort by American and Soviet artists at Boston's Wang Center. Sets designed by John Conklin will be built at the Bolshoi Ballet workshops in Moscow. Conklin's costumes may be made in Leningrad or the U.S., said Bruce Marks, artistic director of Boston Ballet who is overseeing the project.

Marks has been working on plans with Natalia Dudinskaya, a former Kirov prima ballerina, and her husband, Konstantin Sergeyev, who directed the Kirov for 20 years. Dudinskaya's work on a 1986 Boston Ballet production of "Giselle" led to this larger collaboration.

Marks has asked Kirov director Oleg Vinogradov to send principal dancers Altynai Asylmuratova and Konstantin Zaklinsky, a talented husband-and-wife team. Under the plan, two teams of dancers would alternate the lead roles: The Soviet prince would be partnered with an American swan queen and vice versa.

Boston Ballet will fund the production, through private funds, still to be raised.

- PABLO PICASSO'S PAINTING "Maternite" sold at Christie's in New York for almost $25 million, setting an auction record for the artist's work. The auction of paintings and sculpture from the collection of William and Edith Mayer Goetz broke records for the sale of works by eight different artists, including Picasso and Edgar Degas, whose sculpture "Petite Danseuse de Quatorze Ans" went for $10.2 million. All 28 items in the sale sold, netting a total of $85.25 million for the Goetz collection, a record for the sale of an individual collection.

The Picasso, a tender image of a mother kissing her son's up-raised face, was considered a rich revelation of the artist's early work. It sold to an unidentified Latin American buyer. Picasso's previous auction record was $15.4 million for "La Cage D'Oiseaux," still far behind two Van Gogh paintings - "Irises" and "Sunflowers" - as the most expensive work ever sold at auction.

- THE AMATO OPERA, a mom and pop operation in New York's Greenwich Village, has become a New York institution after 40 years. In his tiny theater at 319 Bowery, Anthony Amato has been giving generations of young singers a taste of the exhilaration of the operatic stage, and a grasp on the standard repertory.

Seventeen alumni (including tenor Neil Shicoff) have Metropolitan Opera credits, and more than 25 have sung at New York City Opera. Amato, who comes from a musical family of Italian emigrants, used money from his business jobs to launch the company, whose warehouse home cost $85,000 to transform.

Amato is stage director, conductor and coach. The little company operates on a shoestring, thanks mainly to sets and costumes all created on premises, where his wife, Sally, is chief seamstress.