The Italian coach hopes the Ligue 2 champions will bring in further recruits this summer as they aim to battle Paris Saint-Germain for the Ligue 1 title next season
The Ligue 1 side have already added seven new players to their roster, including high-profile names such as Radamel Falcao, Ricardo Carvalho, James Rodriguez and Joao Moutinho, but the Italian feels they still lack a bit of quality that would allow them to compete with Paris Saint-Germain.
"The club's objective is to finish in the top three, but the team is still missing something," he told the Corriere dello Sport.
"We are missing some players of substance who would really add something to the team. The squad has already changed a lot compared to last year and has become very strong, but we are not complete yet.
"We are still far away from PSG's level, although I understand that the people will see Ligue 1 as a battle between us and them. We have an ambitious president and a lot of money."