A company, looking to go younger, hipper or more demographically diverse, signs a lucrative endorsement deal with that year’s “it” celebrity, hoping the star’s fans will follow, Pied Piper-like, straight to the cash register.

Then a public-relations disaster strikes. Madonna dances in front of burning crosses in her “Like a Prayer” video, and Pepsi, stunned by the blowback, suddenly calls off its multimillion-dollar deal with the singer. Tiger Woods gets caught in a marital scandal of colossal proportions and Tag Heuer, Accenture and AT&T all decide to sever ties. Paula Deen admits to having used racial epithets and loses her place at Sears, Kmart and Walgreens.

But this time it’s different. This time it’s the celebrity (in this case Jay Z, the rapper-turned-corporate-conglomerate) whose carefully burnished image has been potentially tarnished by a deal with a big company (in this case, Barneys New York) going through a public-relations nightmare of its own.

In October, news broke that two African-American shoppers had been detained by the police after making purchases at the Madison Avenue store, setting off protests, calls for a boycott and heated denials from store executives that the store had acted improperly or engaged in racial profiling of its customers. (Similar charges were also leveled against Macy’s, and were also denied by that store’s executives.)

For Jay Z (nee Shawn Carter), the timing could not have been worse.

On Wednesday, he is scheduled to debut his fragrance, Gold, at Barneys, along with a capsule fashion collection that includes backpacks, raincoats and some jewelry, a collaboration that has been heavily promoted by the company in recent months and was supposed to be the occasion of a holiday-season party this week.

As one of the country’s best-known African-American entrepreneurs, he not only performs but is also at the head of a management company that represents talent like Rihanna and M.I.A. Until recently, he was a part-owner of the Brooklyn Nets basketball team and helped broker the deal to bring the Barclays Center to Brooklyn, before expanding into sports management and selling his stakes in both this year because they were considered to be potential conflicts of interest.

He has partnerships with Samsung, Duracell, Microsoft and Budweiser, and co-founded a very successful clothing company, Rocawear. With his wife, Beyoncé, he is part of an almost impossibly glamorous couple and has rarely taken a misstep in his journey from up-and-coming rapper to corporate titan. A reportedly close friendship with President Obama — Jay Z has told reporters that the two text each other on occasion, and the president gave a shout-out to “J and B” at a 2012 fund-raiser the couple hosted, raising a reported $4 million — hasn’t hurt.

But news of the deal with Barneys brought collateral damage to Jay Z as fans began signing online petitions urging him to cut ties. Jon Stewart lampooned him on “The Daily Show.” The Daily News, which broke the initial story, ran a particularly unflattering picture of Jay Z on its cover, along with a headline that shouted “Zero Respect,” with the letter “Z” in red, while in Stockholm (where he was on tour) reporters crowded him on the sidewalk demanding to know his reaction to the incidents.

He has so far refused to speak publicly about the matter — and representatives for him would not make him available for this article — but in a statement published on his website on Oct. 26, he said he was not earning anything in this collaboration, which will benefit lower-income urban youth through his Shawn Carter Scholarship Foundation. He said this endeavor “lives in a place of giving,” reiterating that, with 25 percent of all sales going to his foundation, he was not going to “make a dime.” “I move and speak based on facts and not emotion,” he said. “I haven’t made any comments because I am waiting on facts and the outcome of a meeting between community leaders and Barneys.”

As rock stars are wont to do, he also took aim at the news media calling for him to cancel the collaboration and referred to himself in the third person: “Why am I being demonized, denounced and thrown on the cover of a newspaper for not speaking immediately? The negligent, erroneous reports and attacks on my character, intentions and the spirit of this collaboration have forced me into a statement I didn’t want to make without the full facts. Making a decision prematurely to pull out of this project wouldn’t hurt Barneys or Shawn Carter but all the people that stand a chance at higher education.”

But for some critics, that statement did not go far enough. “Any African-American, male or female, with any consciousness of what has happened would not go into Barneys right now,” André Leon Talley, the former editor at large of Vogue, said in an interview this week. “Nor Macy’s.” He said that if he were in Jay Z’s position, “for the simplicity of making a broad statement I would pull out.”

The casting agent (and former model) Bethann Hardison, who is African-American and has helped lead an effort in the last few years to bring more minorities onto runways, conceded Jay Z is “in between a rock and a hard place.” Still, she believes that at least right now, he ought to put off introducing his fragrance through Barneys until they “work this out.”

Among notable public-relations professionals, the reactions have been more mixed. Mara Buxbaum, a communications strategist for various high-profile clients, said she thought he had done a largely adequate job with the statement he delivered. “It goes down the middle,” she said. “It says, ‘I want to learn the facts.’ ”

Liz Rosenberg, who has represented Madonna throughout one controversy after another (including her lost Pepsi endorsement) agreed: “Good for him for not having a kneejerk reaction.”

But several other communications strategists (who spoke on condition of anonymity as to not jeopardize potential business relationships) had deeper misgivings. As they saw it, there was little to be gained by standing by Barneys and hoping that this blows over. (Though denying either store did anything wrong — and while waiting for the results of an investigation by the state attorney general, Eric T. Schneiderman — executives for Barneys and Macy’s have started internal investigations and organized numerous high-profile meetings with African-American leaders. A group of retailers, including Barneys, Macy’s, Saks Fifth Avenue and Neiman Marcus, is planning to meet Friday to discuss issues of racial profiling, discrimination and loss prevention, according to WWD.)

“He’s a pivotal cultural figure,” one said. “Not saying a peep on something that is as charged racially as this seems like a big mistake. And he’s not made many mistakes since his career exploded. It could potentially really tarnish his street cred.” Several argued as well that taking on the news media and painting himself as a victim was perhaps not the best P.R. strategy at a moment when papers like The Daily News are running headlines like “Busted at Barneys for Being Black.”

Even Ms. Buxbaum seemed to agree with that. “It’s very hard for a celebrity to say, ‘Woe is me,’ ” Ms. Buxbaum said. “When you have that much fame, power and wealth, no one wants to hear you say, ‘Why am I the face of this?’ ”

And that party at Barneys on Wednesday? As of Friday afternoon, no word whether it was still going on as planned.