Glenn kept tabs on Sebastien after he first caught the eye when West Ham faced Metz in the InterToto Cup two years ago, and - when Trevor Sinclair and Steve Lomas got injured - recommended a loan swoop for him to fill the right wing back position.
He has not yet taken up any other offers - some of which are from England - for next season but is certain to leave Metz after a contretemps with a journalist in France.
Ironically, one of the clubs interested in him is Middlesbrough, undergoing their own managerial restructuring at the moment. Bryan Robson cited a major reason for leaving them as being the reception he got after the final match of the season against the Hammers - even though they won it.
"After the reception I received at the end of the West Ham match, I thought it was time for me and the club to move on," he said. "In the first few years I had a great rapport with the fans but when you lose them I think it is time to move on.
That paves the way for Steve McClaren - who earlier had discussions with the Hammers about a managerial post - to join Boro although his arrival has not been officially confirmed yet.
Their chairman Steve Gibson said: "I have talked to Steve McClaren quite frequently over the last week or so, but the matter isn't concluded yet. Steve is on holiday in the States, but we hope to offer some news at the weekend."
None of which makes Sebastien's position any clearer - though Glenn thinks he has adapted well to the English game.
"He was on loan to us until the end of the season which has now come to an end, and now we are in a situation where we are waiting to appoint a new manager so at the moment his situation is in limbo," says Glenn. "It will be up to the powers that be whether they resurrect anything on a permanent basis but I would say at the moment it is on hold.
"There are things that can only be decided by a new manager and until the appointment is made there are things that will just have to rest."
Comparing him with Trevor - with whom he would have to compete for a place next season if he did sign - Glenn says: "I thought Sebastien did very well but he is a completely different type of player to Trevor who is stronger and more physical.
"Sebastien hasn't got the physical presence but he is nevertheless a very good footballer who knows the wing back role well; it is made for him.
"He has got lots of energy and can get box to box easily, and I think on his debut at Charlton on Sky TV he was probably our man of the match - he was outstanding.
"Trevor Sinclair is in through the summer and is looking particularly good - I think he is looking forward to pre-season."
"But it is a quiet time at the moment and the training ground is quite eerie: it seems strange that there are no players coming into the ground every morning."