Hi,

on these. Any experience of it and how it's sorted would be handy before I
get to have a look at it.
On 205's, the common path was the rear light clusters... Since it's a 206,
here's a hint for you : the space beneath the rear seats makes a kind of
pool, where water may be accumulated. My usual suspects would be the
taildoor's seal.
Mine has a similar behaviour, due to an incorrect door clearance (I should
fix it... damn I tell that on any heavy rain day), this letting water go
it's way and making the rear floor carpet wet.

HTH,
--
G.T