Macos Sonoma - Excel wrong number format

I'm using my Mac in Belgium with numbers in a format with comma as decimals and dots (or space) for thousand separators (see screenshot). Seems to be OK in "numbers.app" and is presented correctly as numbers (example 1.235,00).

However, in Excel (last version), numbers are presented with dots for decimals and commas for thousand separators. I've tried everything even a terminal command to force the correct number format for maOS but cannot find the reason why Excel keeps using the wrong number format by default.

Any idea ?