On loan from Lyon for a season, the Frenchman produced a decent performance in the Carling Cup on Tuesday night to help Pompey to a 4-0 win over Stoke.
Piquionne scored twice and set another up and his performance was pleasing for Hart who hopes the 30-year old is now beginning to understand the English game.
"The penny is starting to drop with Frederic," said Hart after the win over Stoke.
"We have a lot of players who haven't played in the Premier League and it's a massive change for them.
"There's an English attitude to the game that Frederic has to acquire.
"He was recommended to us. When we signed him we were absolutely brassic and free sounds good.
"His goalscoring record in France wasn't the best but we hope he'll make goals for people as well."
Piquionne has been frozen out of Hart's first team since September but this performance may convince the manager to include him in future fixtures.