CSV files cant store special characters?

This is a well known issue with saving CSV files in excel, and I do not believe it is possible to solve directly. However an addon such as this one (includes source) can be used to get around the issue.

How does it work?

As Excel can handle Unicode text (*.txt) files perfectly well, I’m relying on that to make this Addin work. On save, this Addin will be calling Excel’s SaveAs method to create a temporary Unicode Text file. It will then overwrite the original file by replacing all Tabs with comma and reload it. As it is a CSV file, Excel doesn’t preserve any column width adjustments or last active cell. Currently this Addin will reset the last active cell, and I think it should be pretty straightforward to reset column widths as well, if you wish to do so.