Tesla Model Y is a huge vehicle.
Because a 1.5t Zoe pollutes even less :P We can argue about the cut-off line, but it'll be arbitrary - the only thing for certain is that the mayor seems to agree with the sentiment.
Because they care bad for the environment. Because they take up a lot of space. Because they are unsafe, especially for others.
Tire and road particles are quite serious. You are correct that an ICE car is worse, and yes in a perfect world we'd ban them entirely. But there are many reasons for why that is difficult. Paying a small tax for extravagant vehicles for the greater good of a community is not a problem.
If anything 2 tons is way too much. We need more incentives to make light vehicles. Not just deterrents for way too big cars.
Like GP mentioned, tires also pollute via abrasion.
> 2 tons is just slightly heavier than a Tesla Model Y, a compact SUV barely large enough for a family of 4
A Model Y by Parisian scale is a incredibly huge car. French (and honestly most European) families get by with VW Golf sized car.
> and more than 2 tonnes for electric vehicles.