Issue: the numbers are loaded as text, when a cell containing such a number is selected, it shows that the number is preceded by a single quote and a space. search for the quote and replace it by nothing does not work.
Solution: When opening the file in open office make sure that detect special number is enabled
If your decimal sperator is a dot, then the number might be changed into a date, turn it off and replace the dot by a coma when the csv is open.
Also the csv file was created with python using utf8-sig which had a BOM each time it happened something to the file. Encoding the file using utf-8 only solved the issue.
Issue remains when you have both number separated by a dot that can be change into a date and integer.