Does audio powered LED light with low tension require CE/FCC certificate?
I can only speak about CE marking. It's no big-deal on this simple product to CE mark (and if it is too small then the packaging needs to be CE marked). It's electrical and my understanding is that it will need CE marking.
Don't despair, for something like this it isn't a minefield of legislation. You need to look-up the list of directives. Here's one I prepared earlier: -

Then you decide which ones may apply - ignore the rest but be concientious and not cynical about this. Liklihood is that several may apply and you prepare a document that justifies why they don't apply OR, if some do you justify why only certain sections of a directive apply. This is called the self certification route and there's a realm of good info here.
This covers you but like i say, don't be cynical about stuff - low voltage directive applies to anything where the voltage is above a certain level and although you are powered from a cell-phone, give a little more than lip-service to why you won't produce voltages that mean you have to comply.
EMC directive might be applicable and maybe you have to throw in some sentences that justifies you won't be interfering with the radio signal in any way - difficult to prove but best have answers documented.
You'll have several days (14 I think) if someone challenges your &quot;right&quot; to CE mark your product so it's best to have the info on-hand in the form of a &quot;technical file&quot;.