The French-speaking world is in mourning for Tintin, a teen-age comic strip hero with a blond cowlick, and his creator, Georges Remi.

The death of Remi, a cartoonist who was better known internationally by his pen name, Herge', is being treated here with the solemnity normally reserved for the passing of a great national hero or statesman. Newspapers have come out with black borders, cabinet ministers have been asked to make statements, and philosophers have been pondering the question of how Tintin changed their lives.

A measure of Tintin's popularity is provided by a remark of Charles de Gaulle, who when he was at the peak of his power, confided to a friend: "My only serious international competitor is Tintin." Evidently thinking that the comparison was to Tintin's disadvantage, one French newspaper today said it illustrated de Gaulle's well-known "megalomania."

In France and Belgium alone, 70 million Tintin books have been sold since Herge' invented the teen-age reporter with the innocent moonface and the baggy plus fours in 1929. The serial has been translated into 33 languages, including five Indian dialects and a Chinese edition that sold 600,000 copies immediately.

In the company of his faithful fox terrier Milou (known as Snowy in the English edition), an irascible sea captain called Haddock, and Calculus the absent-minded professor, Tintin roamed the world in 23 separate adventures. He seems to have despised both communism and capitalism and was most at home in Western Europe--which may be one reason why he never attained quite the same popularity in the English-speaking world.

In Belgium, Herge''s birthplace and the site of a statue to Tintin, news of his death on Thursday became the number one political talking point. The minister of justice described Tintin as "dynamic, courageous, resourceful and very sympathetic," while the minister of finance confessed that he identified more closely with Milou because "I, too, lead the life of a dog."

In France, where much to Belgian annoyance they claim Herge' for their own, newspapers devoted page after page to his obituary and reprints of Tintin comic strips. The popular Paris daily Liberation devoted its entire front page today to a cartoon of Tintin lying face down on the ground with Milou howling "Waooouuu . . . Tintin is dead." Le Matin said simply, "Adieu Tintin . . ."

Reports from the politically important municipal elections, which are being held today and have dominated news coverage for two months, were consigned to inside pages and illustrated with Tintin cartoons.

The philosopher Michel Serres described Herge' as "the author who has had most impact on contemporary French life." In Le Matin, Jean-Paul Kauffmann wrote: "Those who are today aged between 27 and 47 and were by turns Marxists, Sartrists, or Maoists were first and foremost Herge'ins. And many remained so. For Herge' is what stays after everything else has been forgotten."

The Communist Party daily, L'Humanite', was also generous in its praise of Herge', even though Tintin once described Soviet Russia as "a stinking cesspit" and accused Lenin, Stalin and Trotsky of "amassing the treasures stolen from the people." The newspaper headlined its report: "Children Between 7 and 77 in Mourning."

Tintin was accused at various times of being racist, fascist and even homosexual. In fact, as Herge' himself pointed out, his true ethos was that of the boy scout who never grew up--with simple values like defending the weak against the strong and standing up for good against evil.

On one point, Herge' was very insistent. It was that nobody else would be allowed to continue the Tintin legend after his death. "Tintin, c'est moi," he said. "We will disappear together."