Carole Ghosn, the wife of the fugitive former Nissan boss Carlos Ghosn, has insisted she had no idea about his plan to flee Japan and was surprised when he arrived to join in with her festive celebrations in Beirut.

Her comments were published hours before the 65-year-old executive was due to give a press conference in Beirut detailing his flight from Japan on 29 December, where he had been awaiting trial on multiple counts of financial misconduct, which he denies.

Speculation over how he managed to bypass tight bail conditions has ranged from reports of him hiding in a musical instrument case to boarding a bullet train.

In her first interview since the escape Carole Ghosn, a Lebanese-born fashion designer who had been based in New York, told Le Parisien: “I didn’t know about anything. I was in Beirut with my children to celebrate Christmas. Someone called me, saying: ‘I’ve got a surprise for you.’

“It was the most beautiful surprise of my life. We met at my parents’ apartment. I held Carlos very tightly in my arms for at least five whole minutes before I could even speak.”

She said she “never doubted my husband for a second” and repeated the family’s assertion that he had been the victim of a “coup” by former colleagues opposed to his plans to deepen the alliance between Nissan and the French carmaker Renault. She called him “the victim of an industrial plot and the war between Renault and Nissan”.

She said leaving Japan “was his only possible choice” as he was being kept in conditions aimed at “dehumanising him”.

Carlos Ghosn, who holds French, Brazilian and Lebanese citizenships, had been under strict bail conditions which included restrictions on contacting his wife. This was reportedly among the reasons why he decided to jump bail. His wife said that when she had visited him in jail, he was being kept in a cell near “criminals, terrorists, mass murderers” and tattooed gang members.

The couple married in 2016, the second marriage for both, at a sumptuous reception at the Palace of Versailles, with a Marie Antoinette theme and historic costumes.

Last year French prosecutors opened a preliminary inquiry into how Ghosn, the former Renault chief, financed his wedding – and whether the French car firm had footed part of the bill for the private event. Ghosn has denied any wrongdoing linked to the wedding.

Carole Ghosn was a vocal supporter of her husband during his long detention in Japan. This week prosecutors in Japan issued an arrest warrant for her for alleged perjury, a charge not related to her husband’s escape. She dismissed the arrest warrant as “an act of revenge by Japanese prosecutors”.

Nissan has vowed to pursue its former chairman over what it has called his “serious misconduct” while head of the firm.