Yes, in the EU the cutoff point between recreational and commercial is defined by lenght with 24m beeing the cutoff point. Anything over is considered commercial regardless of how it is used. This applies to all EU member nations. Operating a private yacht over 24m is something else and subject to national flag regulations. You need at least a commercial deck officer patent (STCW-95) but some countries have exceptions to the training required, giving commercial endorsements to "yacht training", meaning you don't have to go to university for it. The most famous of this "commercial" tickets is the british Yachtmaster, and this regulation is one of the reasons you see so many superyachts under the Red Duster (the british MCA is also the regulatory agency for a lot of tax havens) and why the RYA Yachtmaster Ocean is so prevalent in the industry. Basicly for a fee you can make it "from zero to hero" in a few months and you are good to go as captain up to 200GT including commercial (charter) service. Other EU states have similar regulations but solely for "traditional boats" (variously defined, but usually something that is or just looks vintage) while others offer no shortcut to a propper STCW-95 training.
From the EU perspective, the US is a unregulated paradise when it comes to licenses and import. As far as I know the only category where the US has really stringent federal regulations in place, are steamboats over a certain size or power where you need a licensed steam engineer to operate and certified boilers.
