Prague has a fairly good road infrastructure, yet this doesn’t mean traffic jams or problems with finding a parking place don’t occur. Also break-ins or vehicle thefts are not excluded. This is why it is mostly advisable to leave your car in safe parking lots, that is in guarded parking places, even if they can be fairly expensive, especially in places close to the city centre.
If you ignored a „No Parking“ sign and you can’t see your car anywhere, it could mean that your car has been towed away or, more dramatically, stolen. In order to get the mystery elucidated, Call 158 or 156 and a police officer will tell you where you have to go to pay the fine and get your car back (that is if indeed it has been just towed away), or will help you declare the theft.
If you find your car clamped, you should call the police at the phone No stated on the bill you find on your windscreen and wait for a police man to come. After paying the fine, the clamp will be removed and you can go. A simple solution to save you from all this trouble would be to Safe Park somewhere further from the centre and use the public transport service. It is cheaper, less stressful and sometimes even faster (e.g. weekday mornings about 8am, when everybody goes to work).