PSG are enduring some well-publicised midfield problems this season, with Lassana Diarra mulling over immediate retirement and Adrien Rabiot falling out with the club.
Rabiot is said to have told PSG he intends to leave at the end of the season and, although he was banished to train alone, the club have reportedly been told to allow him to return to working alongside the rest of the team.
As such, PSG have been heavily linked with a number of midfield options, including Zenit's Leandro Paredes and Bayern's Sanches.
The Portugal international has restored a degree of his reputation this season following an unimpressive loan spell with Swansea City last term and, although he has started only four Bundesliga games, Kovac insists he has no plans to let the 21-year-old leave.
"I made it clear that Renato cannot go, even though PSG was and still is very interested," Kovac told reporters ahead of Sunday's visit of Stuttgart.
"He's doing very well right now, I do not want to give him up. I know PSG has one or two midfield problems, but that's not our problem.
"I'm very happy with Renato, and I'm convinced he will play a lot of games in the second half of the season.
"We will need each player, we saw in the first half of the season. If players fall, we cannot downsize our squad."
Another Bayern player linked with a move is James Rodriguez, with the on-loan Real Madrid midfielder still yet to convince the club to trigger their purchase option.
The Colombia international has played just nine times in the Bundesliga this season and Kovac cannot promise him more regularity.
"James is a top footballer, a great kid, but that's the same for everyone else," Kovac said.
"You have to offer yourself in training, but that does not mean he's doing less [than the others] – on the contrary.
"We got it right last week [against Hoffenheim] with Leon [Goretzka] as the No.10, but I will not and cannot promise anything to anyone.
"I also have to decide on the centre-backs. Everyone trains well, and James did well against Hoffenheim."