It has been reported the fee will become will become mandatory if Inter qualify for the Champions League this season, in which case Rafinha will sign a three-year contract starting from July.
The player's imminent move to Serie A has been confirmed by his father, former World Cup winning Brazilian global Mazinho.
Luciano Spalletti's side are now fourth in the Serie A, behind league leaders, Napoli, Juventus and Lazio.
"With Rafinha, it must be said that Inter are bringing in a Barcelona reserve", the retired midfielder told Sky Sport Italia.
Rafinha only played 15 minutes all season for the Blaugrana, all of which came in the Copa Del Rey.
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"It's very hard to get into the Barcelona side as there are so many players".
"He just wants to play, feel happy and do what he loves at an excellent club like Inter".
He then went under the knife again past year after suffering a meniscus injury against Granada in April. "He's going to take advantage of this chance in Italy", his father claimed.
Rafinha - who has previously spent time out on loan from Barcelona at the Spanish side Celta Vigo - is believed to be keen on a move to the Italian giants since falling out of favour at the Catalan club. He missed the majority of the 2015-16 campaign with a ruptured cruciate ligament and even before injuring his meniscus last season, he'd missed a number of games due to a series of problems.
He scored 11 goals in 79 appearances and won nine titles, including two La Ligas and the Champions League.