Koschmider had converted a couple of strip clubs in the district into music venues, and he initially placed the Beatles at the Indra Club. After closing Indra due to noise complaints, he moved them to the Kaiserkeller in October. When he learned they had been performing at the rival Top Ten Club in breach of their contract, he gave the band one month's termination notice, and reported the underage Harrison, who had obtained permission to stay in Hamburg by lying to the German authorities about his age. The authorities arranged for Harrison's deportation in late November. One week later, Koschmider had McCartney and Best arrested for arson after they set fire to a condom in a concrete corridor; the authorities deported them. Lennon returned to Liverpool in early December, while Sutcliffe remained in Hamburg until late February with his German fiancée Astrid Kirchherr, who took the first semi-professional photos of the Beatles.During the next two years, the Beatles were resident for periods in Hamburg, where they used Preludin both recreationally and to maintain their energy through all-night performances. In 1961, during their second Hamburg engagement, Kirchherr cut Sutcliffe's hair in the "exi" (existentialist) style, later adopted by the other Beatles. When Sutcliffe decided to leave the band early that year and resume his art studies in Germany, McCartney took up the bass. Producer Bert Kaempfert contracted what was now a four-piece group until June 1962, and he used them as Tony Sheridan's backing band on a series of recordings for Polydor Records. As part of the sessions, the Beatles were signed to Polydor for one year. Credited to "Tony Sheridan & the Beat Brothers", the single "My Bonnie", recorded in June 1961 and released four months later, reached number 32 on the Musikmarkt chart.After the Beatles completed their second Hamburg residency, they enjoyed increasing popularity in Liverpool with the growing Merseybeat movement. However, they were also growing tired of the monotony of numerous appearances at the same clubs night after night. In November 1961, during one of the group's frequent performances at The Cavern Club, they encountered Brian Epstein, a local record-store owner and music columnist. He later recalled: "I immediately liked what I heard. They were fresh, and they were honest, and they had what I thought was a sort of presence ... [a] star quality."Epstein courted the band over the next couple of months, and they appointed him as their manager in January 1962. Throughout early and mid-1962, Epstein sought to free the Beatles from their contractual obligations to Bert Kaempfert Productions. He eventually negotiated a one-month-early release from their contract in exchange for one last recording session in Hamburg. Tragedy greeted them on their return to Germany in April, when a distraught Kirchherr met them at the airport with news of Sutcliffe's death the previous day from what was later determined as a brain hemorrhage.Epstein began negotiations with record labels for a recording contract. In order to secure a UK record contract, Epstein negotiated an early end to the band's contract with Polydor, in exchange for more recordings backing Tony Sheridan. After a New Year's Day audition, Decca Records rejected the band with the comment "Guitar groups are on the way out, Mr. Epstein." However, three months later, producer George Martin signed the Beatles to EMI's Parlophone label.

Question: Who was performing in breach of their contract?
Answer: the Beatles