Spoiler Alert for those who’ve not seen all episodes, read no further.
It became apparent at the end that the intended target was in all likelihood the cyclist and the family were in the wrong place at the wrong time.
The botched, amateur investigation by the French made Clouseau look like Columbo.
That in tandem with the unwillingness of the French to delve further into Mollier(cyclist) and his questionable background means this will probably never be solved, sadly.