Also illegal in the EU, when posting a "sale" the price compared to must be the lowest price the outlet had for the product in the previous 30 days. So unless they want to increase the price for over 30 days, this trick isn't going to fly.
For this context with Amazon though, prime is totally different in the EU than the US.
There are few countries with Amazon (eg Germany) and thus for most the benefit is that prime only gets free shipping on smaller orders that wouldn't qualify normally, and faster processing in the warehouse. Maybe you get your shit a day or two earlier.
In the US it's next day vs a week.
Point being there are far fewer prime accounts in EU so Amazon likely doesn't care if they can't discount as "deeply" as in the US.
In the exact wording they speak of a "Trader". It's for both webshops and brick and mortar. And I think it applies to the entity and not the specific shop. So if a company has more than one shop, the lowest price on any of those shops would apply.
Now this is new law and hasn't been fully tested, I'm sure shops will try things to evade this new regulation, but in the past the EU has not taken kindly to shit like that.
In Canada for Black Friday and boxing day they just have new SKUs (models made specifically for sale that day), but these are also usually cheaper than the normal ones. I think they’re actually made from the bottom tier of acceptable parts. So the quality is marginally lower on these models.
Some companies will make special versions for Black Friday that do indeed have cheaper parts or missing features, but for many it's the exact same product as the normal SKU. They do the special SKU at the request of the retailer, to guarantee that no one can use a "price match guarantee" to make them sell more than the planned quantity of door busters.
They get around it by having a sale on a special version of the product that had a higher price in the past 30 to 90 days. The version is the same as normal, but with a different serial number.
Only that version goes on "sale" for Black Friday or whatever, so they are technically following the law. They do it in the US too. Literally look it up on Camel Camel Camel during a sale.
Many places are totally fine with only putting an item on "sale" less than every month. If you keep 1/4 of you items on sale, you're covered, even if you only keep something on sale for a single week.
It's the same story in US and Canada. Illegal, but not really enforced. And when it is enforced the the penalties aren't strong enough to be a deterrent.