Signed by Harry Redknapp for a then record fee of £4.5m, Marc has been described as a true gentleman if ever there was one.
Harry spoke to Sky Sports last night, saying: "Never have I seen someone in better physical condition than Marc.
"Everybody at West Ham loved him and you only had to see the reactions of the French players when they were lining up for the national anthems to see how popular he was in the game.
"Everyone who came into contact with him would have loved the man. He was such a special person and a terrific footballer.
"Sir Alex Ferguson tried to sign him for Manchester United but he broke his leg the day before. I know Alex will be devastated, he spoke to him a lot over the last five or six years.
"Marc was a great young man, it's so sad."
It is a truly sad day for football - a player so young dying in such a public way.
He was a good player for us and should have stayed for longer than he did. He was instumental in one of the best goal's ever scored (Foe to Sincs, Sincs to di Canio, di Canio scores, v Wimbledon). Awesome.
He was a truly nice guy and it is no surprise that the footballing world is so shocked by this.
Our thoughts should be with his family right now.
Rest in Peace Marc