Except that trains don't have the same possible destinations, you can't (easily) take a train to a destination outside EU. I think the gov went in the wrong direction here, the tax for flights within France should have been the highest, to give more incentives for using the train

That's OK. Nobody is forcing you to take the train, you're just being expected to pay for the environmental costs of your decision to fly, should you choose to do so.

>Except that trains don't have the same possible destinations

I do not know of a commercial airport without a train station. There do however appear to be plenty of rail stations that do not have airports.

>you can't (easily) take a train to a destination outside EU.

Britain is about to test this theory. But also, that is nonsense. Passenger trains leave and enter the EU all the time.

> I do not know of a commercial airport without a train station.

I went to a business trip from AMS (Schiphol) to WRO (Wroclaw). Wroclaw airport does not have any rail station (the nearest is a kilometer away). We had to take the shuttle bus to the train station in Wroclaw city centre.

The train from AMS would probably have taken over a day. Excluding check-in and luggage drop-off, flying took less than two hours.

> I do not know of a commercial airport without a train station.

Could you contact me when I would be able to buy a Paris-Tunis train ticket, please?

There are ferries from Tunis to various spots in Italy, at which point you can likely hop on a train.

"I do not know of a commercial airport without a train station"

Leeds Bradford

One is planned to be built though.