Correa scored 30 goals in 117 appearances with Lazio during his three-year spell at the capital club.
At Inter, he will be also be reunited with Argentina teammate Lautaro Martínez.
Inter won its first title since 2010 last season — ending Juventus’ nine-year reign — but shortly afterward coach Antonio Conte left and the club sold two of its top players in Romelu Lukaku and Achraf Hakimi.
The Nerazzurri nevertheless started the season in emphatic style, with a 4-0 win over Genoa last weekend. They visit Hellas Verona on Friday.
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