A Tokyo court on Tuesday upheld a suspended six-month sentence for former Nissan executive Greg Kelly, a one-time aide of the firm's fugitive ex-CEO, Carlos Ghosn.

Both prosecutors and Kelly, a 68-year-old American charged with helping Ghosn attempt to conceal income, had questioned the 2022 verdict, but the Tokyo High Court dismissed their appeals.

Kelly was arrested in 2018 in Japan at the same time as Ghosn, whose detention sent shockwaves around the business world.

Ghosn, a French, Lebanese and Brazilian national, fled the country concealed in a music equipment box the following year while on bail — leaving Kelly alone to face charges.

After the first verdict nearly three years ago, Kelly returned to the United States and has not attended the higher court hearings, his lawyer, Yoichi Kitamura, said.

Prosecutors had originally sought two years' imprisonment for Kelly, accusing him of helping Ghosn underreport his income to the tune of ¥9.1 billion (now $60 million).

In 2022, Kelly was found not guilty on the charges for the financial years 2010 to 2016, and guilty for that for the financial year 2017, with the court handing down a prison sentence suspended for three years.

Ghosn's audacious escape to Lebanon, where he remains at large, left prosecutors red-faced. The former auto tycoon says he fled Japan for fear he would not receive a fair trial.

Separately, French investigators have issued an international arrest warrant against Ghosn over allegations including abuse of company funds and money laundering, in connection with contracts issued by a Renault-Nissan subsidiary.

In December, Honda and the struggling Nissan agreed to launch talks on a merger, which Ghosn told reporters via video link showed that Nissan was in "panic mode."