Brutal punishments mark daily life in Iran

''The day my son received 30 lashes for having attended a birthday party where boys and girls were mixed, I decided to flee the country,'' says a lawyer now living in exile in Paris.

Corporal punishment has become part of daily life in Tehran. The number of lashes varies from 30 to 100, depending on the offense. There are no written laws. Ayatollah Khomeini has said that all laws contrary to Islam are void. So far no new code has been written.

No exact figures are available but jails around the country are overcrowded with political prisoners. After the revolution officials of the Shah's regime were put in jail. Kurdish opponents were the next to be imprisoned, followed by supporters of the former President Abolhassan Bani-Sadr and the Mujahideen-e Khalq.

A few weeks ago, the government-controlled press started to attack the secular nationalists, explaining that former nationalist leader Muhammad Mossadeq was a tool of imperialism and that the oil industry had been nationalized in 1953 under religious pressure. (The nationalization move is generally credited to Mr. Mossadeq, who was prime minister at the time.)

Members of the National Democratic Front are now either in jail or in hiding. Ali Ardalan, a former minister of finances in Mehdi Bazargan's provisional government, was arrested a year ago. He spent 45 days blindfolded and is still awaiting trial. Another man was maintained in jail for a year because he bore the same name as a Kurdish leader.

Detention conditions at Evin Prison in Tehran are said to be terrible. Cells are overcrowded and relatives of the detainees tell of long lines of blindfolded men walking painfully, each of them with a hand on their predecessor's shoulder. Prisoners are regularly beaten.

''They don't have the sophisticated torture devices the Savak (the late Shah's secret police) had. They simply hit. This is sheer brutality,'' says a man who spent a month in Evin.

The prosecutor general of Tehran is Assadollah Ladjevardi, who is responsible for hundreds of executions. Since last March newspapers are no more allowed to publish lists of those executed. Observers in Tehran say that during August and September about 40 executions took place every night.

The number of people executed since the revolution in 1980 is unknown, but the Mujahideen-e Khalq recently published in Paris a detailed list with the names and birthdates of 3,000 of their members who had been shot. In Tehran some assert that 10,000 opponents have been executed so far. People are even said to have been killed by mistake.

Mr. Ladjevardi, the prosecutor general, is a former fabrics seller at the bazaar who spent 13 years in jail under the Shah for complicity in the assassination of a prime minister. He is said to be a psychopath and driven by a deep hate for the Mujahideen-e Khalq.

A few months ago Ayatollah Khomeini asked a respected religious leader to investigate conditions of the jails. After having received the report, Khomeini is said to have summoned Ladjevardi, who answered him that ''any release of the pressure on the opposition would strengthen the terrorism.'' Khomeini eventually acquiesced. But there is growing pressure within the regime itself to get rid of Ladjevardi and his clique.

Conditions in provincial jails are said to be worse than in Tehran. Despite government denials, it is now known that public hangings regularly take place. Recently, Khosrow Ghashghai, a former representative to the parliament and leader of one of the most important tribes in the south of Iran, was hanged in front of a crowd on one of the main squares in the city of Shiraz.

Girls are even reported to have been raped before facing the firing squad. Execution of virgins is forbidden by Islam, so some girls are married by force before being shot.

On the other hand, more and more Iranians are struck by the leniency of revolutionary justice when mullahs are the suspects. Western intelligence sources in Tehran report that Minister of National Guidance Hojatolislam Moadikah, recently arrested by Revolutionary Guards in a clandestine night club, would only have to resign his position. Officially, Mr. Moadikah is unwell and ''will soon retire in the holy city of Qom to strengthen his knowledge of Islam.''

Contacts with justice officials are impossible. Other officials deny that torture is practised on a large scale. Floggings do occur, they concede, but mutilations and stoning have now been forbidden. Those executed, they say, are terrorists who had killed innocent citizens.

Western diplomats who used to press the Shah about human rights are strangely discreet. Says a European ambassador: ''Whatever we say is useless. They don't care about it.''

To ensure its firm grip on the country the government is organizing a huge intelligence service. Phone lines are tapped on a wide scale. Landlords have been requested to provide the identity of all their tenants. Houses are searched one after the other. In the streets, the once very loquacious Iranians don't even dare to greet foreign journalists.