I believe there are the same two classes of certifications as for 2.4GHz Bluetooth radio: regulatory (such as FCC) and trademark (such as "NFC forum" or "ISO" compliance). For active components on 13.56MHz (what you probably call NFC) such as smart card readers you need similar regulatory approvals as for active 2.4GHz devices (FCC in the US etc.) For strictly passive device such as cards/tags (or its emulation in this case) you probably don't need any beside global FCC compliance over whole spectrum but you should check for each market you want to sell. For second group of certificates you can decide if it is worth money to get a sticker on the box. And usually it is. So there are "ISO" (= it means ISO14443 compliance) test suites and certification labs, also "NFC forum" approved testing labs and so on. I'd definitely recommend o run ISO tests at least internally, because this is the only "industry" standard in case that your customer or some reader producer finds incompatibility with your particular product.
