Then there are managers. Though the list has become less. In France currently. Will Still, Liam Rosenior, Ian Cathro at Auxerre, Paris FC and St Etienne, respectivly. Two in L1. One in L2. Until recently Gary O'Niell was at Strasbourg after Rosenior left to go to Chelsea.

Bobby Brown managed USBCO in 2003/4. As far back as 1935, Ernest Payne played for them and managed them from 1937/39. I wonder why he left? Though he did resurface in 1945 as manager of Rouen, and from 1948 to 49 he was at Roubaix Tourcoing

Our own Chris Makin went to Marsielle after a loan spell at Wigan. Simon Stainrod played at Strasbourg and Rouen.

Players that have infiltrated? Sounds a bit of an aggressive or sinister description. I don't know of any player that has 'infiltrated' a football club. They are usually signed by clubs.