Nissan files court claim against Carlos Ghosn's sister

The court claim is not a formal lawsuit.

Carlos Ghosn's legal troubles are far from over, and Nissan has dragged his older sister into the quagmire. The Japanese firm has filed a court claim against Claudine Bichara de Oliveira over what documents describe as "unjust enrichment."

The court claim is not a formal lawsuit. It merely gives Nissan the option of filing a lawsuit if it decides to.

"At this point, this is just a notice to protect Nissan's interest from the statute of limitation. It is not specifically a request for a judgment against Oliveira," the company told Reuters in a statement. It declined to provide additional information.

At the beginning of Ghosn's detainment in Japan, local news outlets reported his Oliveira received about $100,000 annually for an advisory position that served no purpose. It's unclear if the court claim is related to these allegations.

Ghosn remains in a Japanese jail. On December 10, he was formally charged by prosecutors for allegedly under-reporting the income he received while he ran Nissan. He was ousted from his leadership positions at Nissan and Mitsubishi, but he somewhat awkwardly remains the CEO of Paris-based Renault.