It was a busy day at a McDonald’s branch in São Paulo. Marcelo says he was struggling to keep up with demand while manning the chips and white meat stations when the shift boss called him a “damned stupid blackie”.

Marcelo protested and said he would pursue legal action for racism. The store manager fired him the next day, according to his statement in court documents seen by the Guardian.

His is one of 25 individual allegations of racism and sexual harassment found in two of Brazil’s 26 states, which have sparked an investigation by federal labour prosecutors against McDonald’s in the country. The investigation was due to be publicised on Tuesday for the first time.

The complaint came to prosecutors from Brazil’s General Workers’ Union (UGT), who say the cases they’ve highlighted demonstrate a “systematic pattern” of sexual harassment and racial discrimination that they allege are a “widespread standard”.

At the same time as Brazil’s labour prosecutors announced the investigation, 23 new sexual harassment complaints were announced against McDonald’s in the US by the Time’s Up legal defence fund, formed last year to push the #MeToo movement, and the American Civil Liberties Union.

“The complaint presented worrying evidence of sexual harassment and racial discrimination at McDonald’s,” said Alberto Emiliano de Oliveira Neto, the lead prosecutor on the investigation in Brazil.

“It’s a complaint that has broad, national implications that required immediate action from the federal labour prosecutors’ office,” he said, stressing that he could not assess whether the problem was systematic before conducting the investigation.

He said the first action would be to call a hearing with McDonald’s and labour unions.

“We saw a lot of cases involving sexual harassment and racism and because of the quantity, we thought, ‘There is something wrong here,’” said Alessandro Vietri, a lawyer for the labour union. “We need to think about collective rights. Some of the cases get resolved individually but with a company this large we’re talking about public interest.”

“With McDonald’s the issues are recurring and systematic,” said Ricardo Patah, the president of the UGT. “We’re living through a moment where people are speaking up about sexual harassment in a way like never before,” he said, referring to the arrest of a world-famous Brazilian healer named John of God, Brazil’s first major #MeToo scandal. More than 200 woman had made allegations of rape and sexual abuse against the healer: he denies the allegations.

“As a union we are here to show our indignation with this abuse and stop it. Our reaction needs to be as big as the company itself,” Patah said. “Because it can be so humiliating to speak out alone, from the moment this investigation is publicised I am sure the cases will multiply.”

With 1.9 million workers, including in its franchises, in more than 100 countries, McDonald’s is one of the world’s largest companies.

In Brazil McDonald’s is run by Arcos Dorados – Golden Arches in Spanish – the world’s largest McDonald’s franchisee, with exclusive rights to own and operate in 20 countries in Latin American and the Caribbean. The company says it employs more than 90,000 people in Latin America, 73,000 of whom are aged 16-25.

Arcos Dorados in Brazil said it had not been notified about the investigation, but added: “The company does not in any way tolerate discrimination or harassment of any kind. The company also reaffirms its commitment to respect and follow Brazilian labour laws, as well as to providing adequate working conditions to all its employees.”

It said all employees take part in a training course that teaches them to be respectful and adhere to company rules. “The company, as always, is at the disposal of authorities to clarify its practices,” the statement read.

The court documents contain allegations from McDonald’s workers that they were called blatantly racist names by superiors. One case alleges that a man’s female co-worker touched his private parts without his consent and that when the man reported this to his manager, the manager did nothing and claimed the worker was “enjoying it”.

One female employee said her coordinator had embraced her and “stroked” her private parts several times and that her duty manager had once followed her into the bathroom, “intimidating her with malicious invitations”.

In another case, a manager is accused of trying to leverage his position for sex, “caressing” his female employee’s body and saying that, “if she wanted a promotion she would have to give something in return”.

The investigation comes at a time when labour rights have been under attack in Brazil. After taking office in January, President Jair Bolsonaro scrapped the labour ministry and much of the monitoring of workplace practices. Most of the labour ministry’s responsibilities were transferred to the ministry of economy, headed by free-market economist Paulo Guedes.

The National Federation of Lawyers has filed a suit in the supreme court claiming that there is a conflict of interest between the two ministries.