Well, thats a map close to my heart. Average salaries for a university professor. (Annual, in €.) Comments and sources below the map.

Just to be clear:

• This is gross, not net. Go figure. Very roughly, you should expect to pay 40% taxes on your top income slice in Europe, in a progressive tax system. You will need to get your own tax calculator out.
• Different subjects provide for different salaries. Humanities pay less than engineering, etc.
• Different countries have different pension contributions.
• Same for healthcare. Watch out for what is covered for family members.
• Before you all emigrate to Switzerland: different countries have hugely different living costs.

My feeling is that the colouring is roughly correct, but you really need to take a look at the details before you are blinded by a suspicioulsy generous offer.

The source includes a nice breakdown per country and per career stage, and how these figures have been arrived at: https://www.informatics-europe.org/data/higher-education/academic-salaries/professors.html