Short answerPLA cups are not on the EU banned list, but they count as plastic cups, so they carry the required ‘plastic in product’ marking and fall under plastic-packaging rules.
In more detail
Single-use plastic beverage cups remain legal in the EU, but member states must reduce their use and the cups must be marked. Because PLA is a plastic under EU law, a ‘plant-based’ cup is not exempt.
If your goal is to remove plastic, we suggest paper cold cups with paper straws. If customers need to see the drink, PLA cups are an option with the marking applied.
Basis: EU Directive 2019/904, marking requirements for beverage cups.