Recruitment agency help/recommendations (Frankfurt)

I am looking to speak with a recruitment agency that can help me (or may be one you can recommend).

The details are:
I have a colleague who is originally from India. He has been working in the US for some time while his wife has been working in Germany. He has recently moved to Germany to be with her. His visa means he can work in Germany but nowhere else in the EU. The work he does is pretty specialized (banking/software). I do similar work myself so would like to like to take him on at my company. However the problem is the visa issue.

I have taken advice and was told:
Just another idea, could you contract a recruitment agent over in Germany, who would employ your colleague and then you contract the recruiter to provide staff to do the UK contract. This would ensure that all visa issues are correct and are within the relevant legislation. It would mean that your colleague would have to find a suitable recruitment agent and there.

Are you able to help?

Thanks in advance,

Paul