I don’t know what laws pertain in Germany. You should seek competent legal advice from someone who does. I can tell you this, though. Expect huge communication problems. Even when contractors there have a point person in your country, all they do is talk to you via emai and telephone. All questions must go back to their home office. Expect nothing but frustration beyond belief, and then you might be at least a little bit prepared for the reality.
Ask a simple question like can the header have this image as a background, and expect to wait 2 to 3 days—longer if a weekend or one of the many Indian holidays comes in between—before getting an answer back that says something completely unresponsive like, “We already installed head tags.”
We just put a site into WordPress for a poor guy who had his site done originally pure HTML by a firm in India. He wanted it to sell Sports Cards which he posts on Bonanza.com’s shopping cart. The India developers grabbed the About Us text from the Bonanza.com site, and used it as the welcome text right at the top of his Home Page. He wrote text he wanted there instead, and sent it to them, but in 4 months, he was never successful in getting them to substitute his blurb. They simply never could understand that they couldn’t grab a completely different site’s text and post it on his home page, even when it made no sense at all for Sports Cards, it just talked about hoe great a Shopping Cart Bonanza.com is and how Bonanza got started.
Oh, it took us 2 days to fix him up.
I would guess there have to be some firms there who are better able to understand English or German, and actually can follow simple enough instructions, but be prepared for a long and perhaps frustrating search.