"We will give them guarantees for their investments," Iranian deputy foreign minister Mehdi Safari told the Financial Times Deutschland in an interview.
"We are open to all kinds of companies."
Safari, who is to tour Germany in the coming months, said that companies which wished to do so could do business "without a lot of publicity."
A German firm that sought recently to sell a liquified natural gas installation to Iran faced criticism, and the German government subsequently called on others to show "tact" and "moral sense" in its dealings with Tehran.
Iran is subject to international sanctions as a result of its disputed nuclear programme.
