To add to nvoigt's answer:
Even if everyone in the company speaks English, and all internal documents are in English, consider that in many companies you will have to communicate with people outside the company - technology partners, contractors, suppliers, even (gasp) actual customers or users.
There is an even higher likelyhood that some of these people do not (want to) speak English - and even if they do, you will probably have to work with documents they have written or provided (documentation, brochures, bug reports, meeting notes, official regulations), which will probably be in German.
So - in general the answer is no.
The exception would be if a company has an official (and effective) policy of everything having to be in English (documents, meetings, communication with customers). This may be the case in a large, multinational company, but will be quite uncommon in smaller companies. There probably are such jobs out there, but it is not the rule.