If I got 1.0 for Master thesis in Germany, can it be summa cum laude in my CV?
I would think that would be a dangerous move. List what you have the way it was formally granted. If you think it necessary provide a reference to an official definition so that those who don't understand its significance can learn to do so. 

But it isn't really the same thing. Summa Cum Laude is usually (often at least) in the US based on grades for coursework. 

If you are suspected of trying to mislead, it will be bad for you. Tell it like it is.