So while a current genuine Arduino Uno board may carry CE and FCC approval cerifications that doesn't mean that you are in compliance once you either mount a non-compliant shield board (or homemade board) or any external components unless you were to pay to have the completed project certified. I'm not sure how the laws apply in EU, if they apply to individual hobbyist building for themselves or just commercial companies selling products on the market. If it's like most such laws it probably a if you have to ask you are probably in violation case? 