You might want to check into this a bit more.

I am pretty certain that there is a compensation difference at least in the case of UN and NATO peacekeepers. The excuse, of course, may be that the home country of said troops is paying the bill and salaries directly.

In Kosovo, for example the KFOR peacekeepers that were American got paid multiples more than what the others (particularly the Bangladeshis/Pakistanis) did. There are reasons for this differential, many of which are legitimate.

However, the World Bank has been known to have consultants whose compensation they try to peg based on nationality when certain nationals are working outside of their "home" country.