Thank you for your answers. My question has now been answered. I have found the following text in a data sheet for this charger:
Portable charger for electric cars. This portable charger offers you maximum freedom and flexibility
(cable length: 8 metres) when using your electric car. Charge your car wherever you have access to a
230V socket (1-phase) or power (3-phase). The IP65 design offers protection against water and dust.
The charger can be set between 8A and 16A, which allows charging up to 3.7KW (1-phase) or up to 11KW
(3-phase). Suitable for all vehicles with type 2 plugs. Supplied with a protective carrying case for safe
storage and transport.

Because of conflicting answers, I put the question directly to the manufacturer, Blaupunkt, and here's their reply: "It is possible to use 3P3M2T2 (the three-phase model) to charge a hybrid car in 1 phase. The charger simply uses 1 of the 3 phases available in the CEE plug. If you opt for the P3PM2T2 model instead of the P1PM2T2 (the single-phase model), you'll be able to charge a car with up to 11 kW later."

If the vehicle has a type 2 connection, it could work. I initially had a bad contact on my 3-phase socket, which meant that I only had the nominal voltage of ~400 volts between 2 phases. Nevertheless, it charged, albeit slowly. Whether it also charges with a single-phase connection will probably have to be tested.

Hard to say. The fact is that it would need a cable adapter (CEE16 - 3-pole 220V) and another fact is that with around 2kW and a battery of 50kWh it takes a whopping 25 hours to charge. Does that really make sense?

That's a good question. But I can't answer it because we only charge 3-phase

Hello,
It's not possible to charge in single-phase, only in three-phase.

Hello, no, this is not possible and will not work ...

No, it is not possible to charge
single-phase with this charger,
only three-phase, cee 16A socket