As far as I know the abolition of exchange controls years ago and/or the fact that you're taking an intra EU trip (although obviously not intra euroland!) means that you can carry as much cash as you want. However I personally would be very reluctant to carry that amount of cash due to the security risk. Can you mot make alternative arrangements for payment when you get over there - e.g. have the cash wired to the sellers account, preload a credit card and draw the cash out only when required (may have the drawback of less favourable exchange rates than over the counter foreign exchange though?), etc.? Maybe others have suggestions about how best to transfer the case rather than carrying it on your person!