A privately owned German company, Knauf Gips KG, warned its Iranian employees working in Iran that they would be immediately dismissed if caught in antigovernment protests...Iran's government pressured Knauf to issue the order after a senior executive was arrested during Friday prayer demonstrations two weeks ago, according to people familiar with the case. The company, which has 22,000 employees around the world, was told that such a letter would be a condition for the executive's release...Mercedes-Benz parent Daimler...places no restrictions on employees' political activities outside work hours, according to a spokeswoman. A number of major German companies active in Iran, including Siemens AG, Linde AG and BASF AG, said they have similar policies...Knauf General Counsel Jörg Schanow said employees aren't allowed under company policy to participate in demonstrations as company representatives. Knauf's intention with the letter wasn't to forbid its Iranian employees from participating in all demonstrations, he said. "One should exercise some restraint if such actions are going to damage the company," Mr. Schanow said.