Not true. You can have a dash cam, but it has to be the kind that continuously overwrites its own data and only records when it detects an accident. You can also record based on your intent - if your intent is to, say, capture a scenic drive ,then you can do that. If your intent is to just capture the license plates of 1000s of other cars that pass you, you can't do that.

These laws were changed in ~2018 in Austria.