Striker Bunn's father Frank once scored six in a match for Oldham, and Harry - who hit City's goal in the opening 2-1 defeat by Barcelona - is following the family business.
He told City's website: "I always believe that every game I'm going to have at least one chance, so I aim to score from that chance. But it's the players around me who create the chances."
Bunn Senior, now assistant boss at Rochdale, holds the League Cup scoring record - he hit six goals in Oldham's 7-0 third-round win over Scarborough in October, 1989.
Harry said: "My dad used to give me tips - we'd get DVDs of all my games and go through them. He was at the Barcelona game - I'm hoping he'll be able to get over on a cheap flight to Marseille.
"It's our first away trip in the competition and it should be good - we were unlucky against Barcelona and now we want to get the win to put us up there in the group.
"We felt we did well that night - they had a bit more possession than us but with the chances we created, we could have got something out of the game."