Lopes's professional formation took place in Brazil, where he was admitted to the bar in 1977 and began a legal career. São Paulo, the city where he practiced, had grown into Brazil's largest city and a leading center of commerce and industry, which made it a natural setting for business law practice. Later, he pursued graduate legal study in the United States.
Lopes received a Master of Comparative Jurisprudence from New York University in 1979. Founded in 1831 in New York City, New York University is a private research university with a long tradition of professional and graduate education, and its law programs have attracted students from abroad. The comparative jurisprudence degree title points to graduate legal study that compares legal systems across national boundaries.
His Brazilian professional qualification was admission to the bar in 1977, which came before his graduate study in New York and his later career with Demarest e Almeida.
Lopes was a partner of Demarest e Almeida, a law firm based in São Paulo. The firm was founded in 1948 by the American lawyer Kenneth E. Demarest and the Brazilian João Batista Pereira de Almeida, who had led the legal department of the São Paulo Federation of Industries. Its first offices were four small rooms on 15 de Novembro Street in central São Paulo.
The firm built much of its early practice around business clients, including U.S. companies entering Brazil and industrial firms in sectors such as chemicals, pharmaceuticals, and paper and pulp, during the industrial expansion of the 1950s. By 2007 it ranked as the second-largest law firm in Brazil in the Análise Advocacia rankings, and it later occupied a headquarters in the Centro Cultural Ohtake in the Pinheiros district of São Paulo, a building designed by the architect Rui Ohtake.
After his admission to the bar in Brazil in 1977, Lopes practiced law in São Paulo and became a partner in this firm.
