While the SI/ISO 31-0 norm seems to standardize digit grouping around non breaking space, standard space or no space at all, some countries like Switzerland is still widely using non standard characters to group them like the apostrophe.
While we could think this is a corner case, in practice, this isn't. In Calc for example, the default character used to group digits in a number is still defined to the apostrophe when French (Switzerland) is chosen.
Steps to Reproduce:
1. Set the document to the French language (or any other language actually, the problem is the same with other languages as well).
2. Type 1'250.60
3. Via Format > Paragraph..., add a tabulation whose type is set to "Decimal".
4. Press the Tab key to align the number you typed to the tabulation you defined.
Realize the number is not aligned at the decimal separator, but rather at the apostrophe
The number aligned at the decimal separator
User Profile Reset: No
Created attachment 154734 [details]
Screenshot in Writer (LibreOffice 6.3.2) Arch Linux KDE Plasma 5
I confirm it with
Version: 18.104.22.168 (x64)
CPU-Threads: 4; BS: Windows 10.0; UI-Render: Standard; VCL: win;
Gebietsschema: de-DE (de_DE); UI-Sprache: de-DE