Is Old Foreign Paper Money Worth Any Thing?

First, you should see if it is still in circulation by using the internet.
Second, if it is collectible it could bear value.
Third, depending on those two factors will determine value plus the current exchange rate.
There are many counties that the US Dept of Treasury doesn't exchange with so you may want to look into that by looking into their website.

I have foreign paper money from japan germenay france and some other places from the 1940's