Grace Meng urged national governments to intervene, saying she feared that her husband's life was in danger.
Speaking in Lyon, the southeast French city where the international police organisation is based, she said the last social media message she received from her husband came on September 25, depicting a single knife emoji.
"This matter belongs to the international community," Meng told a press conference in English.
She kept her back turned to the reporters present, and refused to be photographed out of fear for her safety.
That day, his wife said he sent a social media message telling her to "wait for my call", before sending the emoji signifying danger.
"I'm not sure what has happened to him," she said.
The agency's secretary general Juergen Stock, who oversees day-to-day operations, said Saturday that it was seeking "clarification" on his whereabouts from Chinese authorities.
Beijing has so far declined to address Meng's disappearance.
It is the latest high-profile disappearance in China, where a number of top government officials, billionaire business magnates and even an A-list celebrity have vanished for weeks or months at a time.
The Chinese effort to track down corrupt officials abroad, known as Operation Fox Hunt, has led to claims in some countries that Chinese law enforcement agents have been operating covertly on their soil without the approval or consent of local authorities.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)