Iran is a vast and beautiful country but unfortunately the quality of life is not that high.let me be different and put aside my rose colored glasses.let me tell you the truth.since you are from Germany, prepare to be shocked by the huge traffic,polluted air and horrible public transportation system.as a tourist you will not enjoy using the public transportation ,it's always crowded and mostly the signs are written in Persian.
Iranian people are facing a huge economical problem due to the wrong political decisions made by our politicians.our country is not in a good place and every young person wants to immigrate to Europe or north America.unemployment rate is so high,young people are facing a lot of pressure by the Islamic totalitarian government. so keep in mind that you are not walking in a safe country. when the unemployment goes high the crime rates always increase.
So it's best to find a local guide and travel with that person.it's better to choose a guy and not a girl.cause the police might arrest you for walking with a girl who is not your wife.it's just the stupid rules of this country which we the people didn't agree to it.
but don't let these truths change your mind. come and see iran and enjoy.stay a week in tehran and then go to other historical cities like isfehan,kashan,shiraz,kerman,hamedan,kermanshah and so on.finally you are lucky that you are a man because i won't recommend a single woman to come here.it's not a safe country for a woman by herself.if they want to come,they should come with a guy. i know this comment is not rosy like other comments but some one has to say the truth.