I just wonder, why you have Europe/London timezone, as you should be in Europe/Paris. Please check the timezone setting in you Joomla profile also.
So this problem has 2 parts:
1. timezone is wrong you should be in Europe/Paris
2. Outlook doesn’t handle Timezones without timezone specification in the .ics file.
As I see there are 2 ways to fix it: either I convert the dates to UTC, or I have add timezone definitions (and find out why you are Europe/London instead of Europe/Paris)
Which version of Joomla are you using?