While enjoying a night out at a Japanese restaurant in his hometown, Firmino reportedly bought a round of beers for the 200 other patrons in the restaurant, manager Ede de Cassia told the Brazilian publication.
De Cassia said: “He spent the whole night taking pictures, always very polite.
“Then he simply called me and said ‘how many people do you have here?’, I said between 200 and 300, and he said that he could buy a round of draught on his account."
The 26-year-old is enjoying an extended holiday after having spent the summer with the Brazilian national team at the World Cup.
There, Firmino made just four substitute appearances for the national team, as manager Tite preferred Manchester City's Gabriel Jesus to him.
Despite the limited playing time in Russia, Firmino managed to score once.
Firmino will join back up with the Liverpool squad at a training camp in the south of France at the end of July, to begin his pre-season training, but until then he is on holiday - and has chosen to spend some of it back in his hometown.
The 26-year-old grew up in the neighbourhood of Trapiche in Maceio - the state capital of Alagoas - before leaving for Figueirense in 2008 as a 17-year-old.
Before he moved, he played in the youth ranks of Maceio's own football club CRB - or Clube de Regatas Brasil.
The current number nine at Liverpool is a popular figure among both teammates and fans, with the Brazilian's selflessness demonstrated both on the pitch, and reflected in his attitude off it.
Last season, he scored 27 goals and assisted 17 times in 54 games in all competitions, and signed a new five-year contract with the club in April.