The 19-year-old forward, who has impressed in the Premier League this season, was eligible to represent Portugal through his mother and grandmother, while also qualifying for Ivory Coast through his father.
However, Kroupi has chosen to remain with France, having already enjoyed an impressive youth career with Les Bleus.
Speaking to Portuguese outlet A Bola while unveiling his provisional squad, Martinez admitted Portugal explored the possibility of securing the youngster’s commitment.
"Yes, there was interest, we stayed ahead of the news. Before the March training camp we had contact - it is important to follow players who can represent the Portugal national team and those who want to represent - Junior wanted to play for France and we respected it, it is a case that we left closed," he said.
Kroupi has scored 15 goals for France across several youth levels, making the 2022 World Cup finalists favourites for his senior international future.
Bournemouth have also benefited from the attacker’s rapid rise since his €15 million transfer, with the youngster scoring 12 Premier League goals and adding two more in domestic cup competitions this season.