Ms. Abate, the McDonald’s spokeswoman, said the company disputed the accusations in the suit, but declined to answer specific questions about it.

Representatives for the franchisee of the outlet where Ms. Deslandes worked, Bam-B Enterprises, declined to comment on the details of her suit. Bam-B is not named as a defendant in the case.

Turnover rates are high in the industry, and maintaining a talented work force requires investing in training and recruitment. Prohibiting franchisees from hiring one another’s workers protects that investment, said Stuart Hershman, a lawyer with the firm DLA Piper. He estimated that he had drafted hundreds of franchise agreements, many of which contained some kind of recruitment prohibition.

“There has never been, ever, any intention, by drafting this type of provision, to restrict employee mobility, restrict wage competition, or suppress employee pay,” Mr. Hershman said.

There is no good measure for how often workers are restricted from changing jobs, and some franchisees interviewed by The New York Times were not aware that their ability to hire was restricted. It is also difficult to gauge what impact the hiring rule has on wages. But the prevalence of no-hiring agreements in franchise contracts suggests that “many employers do try to combine to restrict competition in the labor market,” Professor Krueger and Professor Ashenfelter wrote.

“It might help explain a recent puzzle in the U.S. job market,” the two wrote in their report. “Unemployment has reached a 16-year low and job openings are at an all-time high, yet wage growth has remained surprisingly sluggish.”