John Joseph Boswell, the chief executive of a barrel manufacturing company, pleaded guilty to misdemeanor sexual abuse for groping a maid at the Mayflower Hotel in Washington. (Special Collections Research Center)

He was a millionaire, in Washington to toast President Trump’s inauguration.

She was a maid, tasked with cleaning rooms that cost more in a few days than her monthly rent.

On Jan. 19, as the nation’s capital swelled with tourists and protesters, the millionaire and the maid met on the 10th floor of the Mayflower Hotel downtown, in Room 1065.

As she made his bed, he approached from behind and began rubbing her buttocks, according to a police report.

“This is very nice stuff,” he said, according to the report. “I like that!”

Such incidents are all too common in an industry where about half of employees say they have been sexually assaulted or harassed by a guest, union surveys have shown. Many go unreported because the housekeepers, often immigrants or women of color, fear losing their jobs.

In 2011, the plight of hotel housekeepers became international news when Dominique Strauss-Kahn, then the head of the International Monetary Fund, was accused of sexually assaulting a maid at a luxury hotel in New York. Criminal charges were dropped, but the incident spurred New York hotels to provide maids with panic buttons.

Six years later, the devices only now are reaching many other parts of the country, including the District, a city with 32,000 hotel rooms and about 3,000 maids.

More than 30 hotels in the Washington area have introduced panic buttons in the past year under an agreement with Unite Here Local 25, said John Boardman, the union’s executive secretary-treasurer. The Mayflower introduced the devices on April 1, he said.

The agreement was reached in 2012, but it has taken five years to put in place reliable technology, Boardman said. When pressed, the panic buttons send a maid’s location to hotel security. Hotels pay for the devices and monitoring systems, which generally cost between $40,000 and $50,000.

In November, voters in Seattle approved a measure providing hotel workers with panic buttons and other protections. And in Chicago, the city council is considering a measure that would require panic buttons.

“These women deal with a constant fear when they work by themselves,” said Alderman Michelle Harris, the ordinance’s sponsor. “Will they be next?”

Vanessa Sinders, a senior vice president for the American Hotel & Lodging Association, which represents most of the country’s biggest chains, said the industry is committed to using technology to keep its employees safe.

“Unfortunately, when it comes to sexual harassment,” she said, “no industry is immune.”

[Bill Dean throws wild Georgetown parties. Now a rape is alleged at one.]

Perhaps the only thing unusual about what happened in Room 1065 was that the man was arrested.

John Joseph Boswell pleaded guilty last month to misdemeanor sexual abuse in D.C. Superior Court. He was sentenced to 10 days incarceration and six months probation, although the jail time was suspended.

The maid declined to comment. The Washington Post generally does not name victims of sexual assault.

In an interview with The Post, Boswell maintained his innocence.

“I patted her on the lower back,” said Boswell, 70, who is married and has three young children. “It was just a friendly gesture.”

The prosecutor in the case saw things differently.

“He took advantage of [her] while she was working, vulnerable, and alone,” Vivian Kim, an assistant U.S. attorney, wrote in an email to Boswell’s attorney.

Two different Americas collided at the Mayflower that afternoon.

The woman is an African immigrant who cleans strangers’ rooms for $20 an hour.

Boswell is the chief executive of Independent Stave Company, the world’s largest wine-and-whiskey barrel manufacturer. He lives in a 14,000-square-foot, $7 million mansion in Palm Beach Gardens, Fla., 20 miles from Trump’s Mar-a-Lago estate.

Boswell — who has contributed more than $120,000 to Republican candidates and conservative groups over the past 25 years — wasn’t always a Trump backer. In the 2016 presidential election, he supported Ben Carson and Sen. Marco Rubio (Fla.). But by the time of Trump’s inauguration, Boswell had embraced the new president and booked a room at the Mayflower.

On the morning of Jan. 19 — the day before the inauguration — the maid commuted from her modest apartment in Riverdale, Md., to the historic hotel, with its gilded ballrooms and crystal chandeliers.

It was about 2 p.m. when she entered Boswell’s room, and he began touching her.

She froze and, in shock, apologized to him, according to the police report. “Sorry sir,” she said. “Sorry sir!”

When another maid emerged from the bathroom, Boswell “immediately moved,” the report said. The first maid rushed out of the room, shaking, and told her co-worker that she would have to clean it by herself.

As the second maid attempted to make the bed, Boswell approached her, too, and “placed his hand on the top of her shoulder” until she ordered him to sit down, according to the police report.

Neither woman reported the incident. But the next day, when a co-worker told a manager what had happened, police were called.

At 6:20 p.m. — as the parade for the newly sworn-in president was winding down and supporters and protesters were still clashing in the District’s streets — police knocked on Boswell’s hotel room door. When he stepped out, the maid identified him to officers, and he was arrested.

He was jailed alongside more than 200 protesters, including black-clad anarchists accused of smashing Starbucks windows and torching a limousine.

When he was released the following afternoon, Boswell emerged from the D.C. Superior courthouse — less than a mile from where Trump had been sworn in — wearing a green flannel shirt, jeans and glasses.

At first, the crowd cheered, mistaking him for a protester. Then someone who had been in court when Boswell was charged shouted that he was a “sex offender.” Protesters began throwing things at him. An orange slice struck Boswell in the head.

“Well, that wasn’t very nice,” he told a Post reporter, wiping the fruit from his forehead before walking back toward his hotel.

Boswell’s attorney, Bernard Grimm, pushed prosecutors to grant his client a deferred sentencing agreement, or DSA, under which Boswell would have admitted guilt but then, after a short period of good behavior, could have withdrawn his guilty plea.

Kim refused, pointing out that Boswell “could have potentially faced an additional charge based on similar conduct with another hotel employee the same day.”

On April 11, Boswell pleaded guilty. Court documents show that Boswell earns $600,000 a month, but Judge Michael Ryan ordered him to pay $50 into the crime victims compensation fund — one-fifth of the maximum penalty for the offense.

The judge and the prosecutor also agreed that Boswell could travel overseas while on probation. Last month, he was allowed to fly to the Bahamas. At the end of this month, he is scheduled to spend two weeks in the Dominican Republic for a family reunion.

Meanwhile his victim was so frightened by a visit from Boswell’s defense team to her apartment that she moved, said a co-worker, who spoke to The Post on the condition of anonymity.

Although the two women still work together at the Mayflower, they don’t talk about what happened in Room 1065.

“Whenever she would talk about it,” her co-worker said, “she would cry.”

Jennifer Jenkins contributed to this story.