Wauquiez, who was elected leader of the mainstream right Republicans party last December, was secretly taped making the startling allegations during a lecture he gave at a business school in the central city of Lyon this week.
They were broadcast on Friday by the popular Quotidien show on the TMC television channel.
On Saturday he hit back with a statement alleging that the recordings were illegal and unethical and "open the way to legal consequences".
According to Quotidien's report, Wauquiez started his lecture by insisting that his remarks remain private so that he would not be limited to speaking "the bullshit I might come out with in a media studio".
He went on to express himself with extreme freedom, making less than gentlemanly remarks about German Chancellor Angela Merkel's Instagram account and alleging that:
Sarkozy "got to the point where he was checking the mobile phones of people entering cabinet meetings. He tapped them to get at all the emails, all the SMSes and check what all his ministers were saying when they were going into cabinet."
Macron "objectively had a better alignment of the planets than he could ever have hoped for [in last year's presidential election]. That Fillon wins the [mainstream right] primary, that he destroys him ... I'm absolutely convinced that he organised, I think they made a major contribution to the creation of the demolition cell."
Budget Minister Gérald Darmanin, who was the subject of rape and sexual abuse accusations, "knows very well what he did" and "will fall", like Jérôme Cahuzac, a budget minister under the previous government who has been convicted of tax evasion charges he initially denied. Commenting on his Republicans colleagues' reluctance to condemn Darmanin, Wauquiez speculated that several were thinking "Let's hope that doesn't happen to me."
The rape inquiry into Darmanin was dropped on Friday, although another accusation of abuse of influence to obtain sex has yet to be investigated.
Laurent Wauquiez threatens legal action over recording
Déclaration suite aux propos diffusés par l'émission Quotidien. pic.twitter.com/VyTilABubWLaurent Wauquiez (@laurentwauquiez) 17 février 2018
"These words were spoken in a private teaching context in the course of free discussion with the students, sometimes in a humorous tone," Wauquiez's statement said. "The lecture especially led the students to think about the rumours and fantasies that nourish political life.
"It never, for example, entered my mind to assert that there was surveillance of members of the government during cabinet meetings."
But it emerged on Saturday that he had apologised to Sarkozy, whose associates "categorically denied this grotesque story".
Wauquiez's rebuttal did not convince Macron's supporters.
"Slander, insults, vulgarity ... a strange idea of education," tweeted government spokesman Benjamin Griveaux.
"This exposes who Laurent Wauquiez is, in all his viciousness and in the manipulation of opinion," the parliamentary spokesman of Macron's Republic on the Move party, Aurore Bergé, told franceinfo TV.