The year is 2023 and I'm applying for a postdoc at Paris Saclay university, and I wonder how should I adjust my expectations. I don't want to appear overpriced, but also I don't want to just scrape by. This website says that I should ask between 3000 and 5000 EUR net per month. I would ask for 3000, not to scare the professor away. Is this reasonable?
Academic salaries in the EU are typically assigned based on the number of years of experience and sometimes taking in account your previous salary. You might be able to negotiate a tiny bit, but usually not much.
According to Glassdoor, postdoc salary in Paris-Saclay is 30k-37k EUR per annum. For more accurate estimate, check the website of the University for the payscale or ask the HR/PI this information.
Postdoc salaries in France are fixed on a national scale. If you have less than two years' experience, your salary will be around €2300 after tax (something like €3000 before tax). If you have more than two years' experience, it will be around €2900 after tax (closer to €4000 before tax). As far as I know, these numbers are non-negotiable. Perhaps there will be some flexibility if you are paid from an individual grant rather than university/national resources. You can ask, but be prepared for the answer to be no.
Having said that, if your lifestyle is moderate, even €2300 is plenty sufficient to live on, especially in the environs of Saclay which is much cheaper than Paris centre. If you don't mind living in a small apartment, even central Paris is affordable -- and life is generally more interesting there than in the towns around the Saclay plateau which are nearly all solely populated by physicists...
You will likely also be able to get 50% of your monthly travel costs reimbursed too, which for a daily commute from Paris to Saclay is a non-neglible amount (~€80).
Source: I was a postdoc in Saclay from February 2022 - October 2023.