I don't think Airtable has the formatting settings for the field that you need to do this. I think the issue comes from Airtable interpreting the comma as a thousand separator, and not a decimal. It may be smart to email Airtable support about this to request it as a feature — there are probably others that also want to change the decimal symbol from a point to a comma.
As a workaround, perhaps you can change the csv file using find and replace to either remove the thousand separator or change the decimal symbol from comma to point?
Thank you. I need to make sure that most of my input is automated, so in the end, I added a few columns (that I can later hide) to make it a bit easier. I added a formula column dividing my amount by 100, giving me the correct amount I needed. It is long-winded, and I had to add about five extra columns, but that works for me now.
Airtable should look at this issue as many people want to use it as a budget tool or expense tracker, and the 1000 decimal separator makes it difficult.