PARIS — A young French teacher arrested on spying charges last July for photographing demonstrations in Iran will be allowed to leave the country after paying a fine of about $300,000, her lawyer said in Tehran on Saturday.

The teacher, Clotilde Reiss, 24, has been in the custody of the French Embassy in Iran after spending six weeks in jail. Her lawyer, Mohammad Ali Mahdavi Sabet, said a court had convicted her but reduced a 10-year sentence to the fine. He said that he would retrieve her passport on Sunday and that she would be able to leave Iran.

The French Foreign Ministry spokesman, Bernard Valero, said in a statement that “we have taken note of the legal authorities’ decision concerning Clotilde Reiss and are therefore expecting her return without delay.”

French officials have said the charges against her were baseless and also denied that her release was in exchange for a French court’s decision on May 5 to deny an American extradition request for an Iranian businessman accused of violating the trade embargo against Iran. Iran praised the court’s action as “a positive point in Franco-Iranian relations.”

Justice Department officials in Washington said that they suspected that the release of the businessman, Majid Kakavand, 37, was a quid pro quo for the release of Ms. Reiss.

Ms. Reiss was arrested at the Tehran airport on July 1 as she prepared to leave the country after a six-month teaching stint in Isfahan. She had participated in demonstrations against the Iranian election in June that kept President Mahmoud Ahmadinejad in power and that was widely viewed as rigged. She took photographs of street clashes and sent them via e-mail to friends, as well as to the French Embassy.

Foreign Minister Bernard Kouchner has called the charges against her “absurd,” and President Nicolas Sarkozy dismissed them as “pure fantasy,” while Mr. Ahmadinejad said in December that her release would depend on “the approach and behavior adopted by French officials.”

Mr. Kakavand was arrested by the French authorities on an American warrant in March as he arrived in Paris with his wife for a vacation. He was accused of buying electronic instruments through a Malaysian company and shipping them to state companies in Iran engaged in nuclear research.

He was released on bail in August and, after the verdict, his bail and passport were returned to him and he left immediately for Tehran. American officials said they would try to pursue their case against him.

Ms. Reiss’s father, Rémi Reiss, told Agence France-Presse that Ms. Reiss was not a political person. “Her motivation is art, culture, knowledge of Iran and its civilization,” he said. During her period at the embassy, she read a great deal about Iranian history, officials said.