 Roussin returned to sea in May 1828, flying his flag aboard the ship of the line "Jean Bart".He led a squadron to Brazil to persuade, through gunboat diplomacy if need be, the Brazilian Emperor Pedro I to pay compensation for French ships captured by the Brazilian Navy during the Cisplatine War.He arrived off Rio de Janeiro on 5 July 1828 and simply sailed into the harbour, ignoring the guns at the entrance, anchoring off the city.