More than one Blues star has been linked with nouveau riche PSG in recent days, especially after it emerged Ancelotti would be their new manager.
The former Chelsea boss was finally unveiled this afternoon and is expected to be given a huge transfer war chest by the French club's billionaire Qatari owners when the window opens on Sunday.
But any approach for one or more of the players Ancelotti managed for two years at Stamford Bridge would be rebuffed, according to his successor.
"They're not for sale," said Villas-Boas, who accepted managers often tried to sign their old players after taking over new clubs.
"It's a situation that can happen."
Villas-Boas himself failed to land Porto wing-back Alvaro Pereira after leaving the Portuguese champions for Chelsea this summer, while he has also been linked with Joao Moutinho and Hulk.
He added: "There's always that possibility because you get to know people from the past."
Didier Drogba, Florent Malouda, Salomon Kalou and even Frank Lampard have been linked with January moves away from Chelsea, who are looking to offload Alex and have already allowed Nicolas Anelka to join Shanghai Shenhua.
Villas-Boas refused to rule out further January sales but insisted the Blues had "no interest" in letting anyone else leave.
Malouda this week publicly admitted he would be prepared to move on in search of regular first-team football, while fellow forward Kalou is seeking assurances of more game time before signing a new contract to replace the one that expires this summer.
Drogba, who is also a free agent at the end of the season, has already rejected a one-year extension to his Blues deal and he and Kalou are less than two days away from being able to pen a pre-contract agreement with a rival club.
Villas-Boas conceded Chelsea might not be able to match the wages on offer at PSG, or in emerging markets like China, but warned almost any move from Stamford Bridge would be a step down.
He said: "We are speaking about new ambitions, new clubs with great financial power being involved in great transfer market activity. That can attract players.
"But look at what is being built here and our recent history in the Premier League, of winning titles.
"We've had European trophies and great FA Cup wins, but the most successful period of the club has happened from 2000 onwards. I would say this plays a part in any player's ambition.
"You get that impression from players when you interview them when they arrive here.
"It is possible to make a step forward from this club, but they're few and far between.
"PSG are a club that, for quite some time, have been desperately trying to win the French league. Great investment, great turmoil in terms of managers and ownership changes from 2000 onwards.
"There's big investment now with the Qatari owners, but I'm unsure whether players would respond to their call as they would from the most prestigious clubs out there."
When Roman Abramovich bought Chelsea, they had more financial clout than any other club on the planet.
But Villas-Boas accepted they had been overtaken and could fall further behind non-European teams during the era of Financial Fair Play.
That could ultimately affect their ability to attract players as well as keep the ones they already have.
"There are players with ambition who want to be continually challenged in this environment," Villas-Boas said.
"Others take into consideration social lives and family lives for the future.
"We are speaking about emerging markets able to pay what we cannot pay.
"It's pretty nice to appeal to a club's crest, but you have to understand your family's future is at stake sometimes, even if players are already earning wages abnormal to normal levels."
Chelsea are no paupers, however, and Villas-Boas refused to rule out spending big in January a year after the club splashed a record £75million on Fernando Torres and David Luiz.
"We are looking for talent, above all, always looking for the best talent available," said Villas-Boas, who was hopeful of reaching an agreement with Bolton's Gary Cahill over personal terms.
"January is difficult because the talent is not (always) available. If it is, it's available at extra cost.
"Hopefully we finish this deal with Cahill and then, regarding the forward situation, we will have to study and decide whether it's worth it or not."