There was a period in the 1960s when Régine Crespin seemed to be carrying the French flag single-handed on the international opera circuit. French singing was at a low ebb and only a handful of native artists received big engagements abroad. The Opéra itself was in poor shape. But there was Crespin at the festivals of Bayreuth, Salzburg and Glyndebourne and firmly ensconced at the opera houses of Chicago, Buenos Aires, Covent Garden and, most especially, the Met in New York.

During this time she took on the grandest soprano roles in the repertory, moving easily from Wagner to French opera and back to Richard Strauss. Perhaps the part for which she will be most remembered is that of the Marschallin in Der Rosenkavalier, which brought out all her special femininity. On stage she exuded warmth and charm in her voice, a distinctively timbred dramatic soprano of vast proportions, and in her arresting figure.

But this sensuousness was a curse as well as an asset. At the start of her career she had an affair with a conductor twice her age. Her marriage to Lou Bruder, an Alsatian poet and translator, was stormy and unhappy. She turned, with disastrous results, to a handsome South American, who turned out to be homosexual, and later to another conductor, Henry Lewis, the exhusband of Marilyn Horne.

If that were not enough Crespin had to remould her voice, turning from soprano to mezzo roles, and her career was later interrupted by cancer. Much of this is told in her autobiography La Vie et l’amour d’une femme (1982), one of the frankest and raciest books written by a diva. In it Crespin holds nothing back, just as on stage and in recital she gave everything to a public which held her in the greatest affection. Except in Paris. There she was at times treated miserably by the Opéra and by a section of its audience.

Régine Crespin became a singer almost by accident. Her much-loved grandmother, “Mannolini”, was of Italian stock and encouraged visits to the theatre. Her father was a good amateur baritone and ran a successful shoe business in Nîmes. She was set for a career as a chemist before she managed to fail her baccalauréat.

She had, though, won a few singing competitions with an aria from Reyer’s almost forgotten opera, Sigurd, and she obtained a scholarship to study at the Paris Conservatoire. Paris was reckoned by her provincial parents as being a city of sin, but they did provide their daughter with a hamper full of the foodstuffs of the south when she made her way to the metropolis. Her fellow students at the Conservatoire included Michel Roux and Gabriel Bacquier.

Crespin carried off two first prizes and one second at the Conservatoire, but the Opéra turned her down at audition, which she did not forget. She moved straight away to the provinces and made her debut in 1950 at Mulhouse as Elsa (Lohengrin). Eighteen months were spent moving around the regional houses, including that at Nîmes, before she made her Opéra debut in 1951 also as Elsa. Andre Cluytens conducted that performance and he was to become important in Crespin’s life. So too was another and lesser known conductor, Edmond Carrière, with whom she fell passionately in love, although he was 25 years her senior.

Crespin moved ahead fast in her late twenties, singing her first Marschallin at Marseilles and at the same house her first Sieglinde in German. Cluytens introduced her to Wieland Wagner, who surprised everyone by casting her as Kundry in a grand Bayreuth Parsifal, conducted by Knappertsbusch in 1958. In it she provided Wieland Wagner with the sensuous Mediterranean sound he longed to hear in the role. That established Crespin on the international circuit. She came to Glyndebourne the following year as the Marschallin (the first time she had sung the role in German), with Söderström as an enchanting Octavian. Crespin’s Marschallin was one of extraordinary graciousness and womanly warmth.

The other main event of 1959 for Crespin was the first Paris performance of Poulenc’s Les Dialogues des Carmélites in which he assigned her the role of Madame Lidoine. Composer and soprano became good friends. Nearly 20 years later she was to return to Carmélites in John Dexter’s memorably austere production at the Met, this time in English and her voice much changed, as the Prioress, Mme de Croissy. It was in this role that she was to appear for the last time at Covent Garden in 1983.

Almost inevitably Crespin’s Covent Garden debut, in 1960, was as the Marschallin, but she was also a notable Tosca, a role in which she made her American debut in Chicago in 1962. On stage she was mesmeric – imperious and flirtatious by turns.

By this time she had married Lou Bruder, who introduced her to German culture, a considerable advantage at a period when she was working more and more in German opera. But Bruder, perhaps overanxious not to become known as M Crespin, treated her both roughly and badly.

She put up with the marriage for some years, not least because her career was prospering. She was a regular visitor to Covent Garden in the early 1960s, and in the theatre she could play the grande dame. She arrived one day to rehearse the role of Leonora ( Fidelio) in full maquillage, bouffant hair style and a pair of violet ski pants. The producer greeted her with the words: “You don’t look much a jailer’s assistant.” Crespin’s reply was instant: “Pouf,” she exploded, “I am Madame Crespin.”

At the Met, Lotte Lehmann, probably the greatest of all Marschallins, directed her in Der Rosenkavalier. Von Karajan invited her to the first Salzburg Easter Festival in 1967 as Brünnhilde in Die Walküre, a role that she repeated at the Met. But it was too high and too taxing for her and was soon abandoned. Nonetheless, Crespin got on well with martinets such as von Karajan and Rudolf Bing and worked admirably with them.

At home, matters were far less happy. A section of the audience at the Opéra had taken against Crespin and started to boo her. Her marriage with Bruder was deteriorating and her vocal control, especially of the upper register, was becoming uncertain. She had also become infatuated with a rich and handsome Argentinian, Victor-José, whom she met while appearing at the Teatro Colón in Buenos Aires. The liaison was doomed from the start: Victor-José’s preferences were not heterosexual and in any case he was soon to die.

Crespin’s private life affected her vocal technique, as many a singer had suffered similarly in the past. She underwent psychoanalysis and retrained her voice to emerge as a mezzo, singing roles such as Carmen (a little too bourgeois) and, more successfully, Charlotte in Werther. The idea of casting her as the Prioress in Les Carmélites was inspired. At roughly the same time, the 1970s, Crespin was able to show the reverse side of her talent by being splendidly extrovert in the title role of Offenbach’s La Grande Duchesse de Gerolstein.

But she suffered a reverse just when things appeared to be going well again. In 1977 cancer was diagnosed. It was operated on successfully, but her appearances on stage became rarer.

In 1989 she bade farewell to the stage in Paris as the Countess in Tchaikovsky’s Queen of Spades, and she devoted more and more of her time to the recital room, where her perfect diction and good taste suited the French chanson especially well. She also gave a greal deal of her time to teaching, which she adored. On the faculty of the Paris Conservatoire for more than 15 years, she was also in enormous demand for master classes.

Both in her prime and in later years, she was honoured by her country many times, including admission to the Légion d’Honneur, of which she was appointed Chevalier in 1972, Officer in 1982 and Commander in 1994. Crespin had no children.

Régine Crespin, French opera singer, was born on March 23, 1927. She died on July 5, 2007, aged 80