Jean-Claude Rouget labelled Sottsass "exceptional" as the Prix du Jockey Club hero aims to became the become the first home-trained winner of the Prix de l'Arc de Triomphe since 2014.
Rouget - who also runs the supplemented Soft Light, added to the field on Wednesday morning at a cost of €120,000 - has never won the Arc.
Having completed his preparation at Deauville on Tuesday morning, Sottsass heads the home team's defence as they try to prevent Enable completing a hat-trick
Treve was the last French-trained winner when becoming the seventh horse in history to win the great race twice.
Enable has since matched her feat and is an odds-on favourite to achieve what Criquette Head-Maarek's mare could not manage.
Rouget has provided a most positive bulletin on Sottsass after his final gallop.
He said: "We just wanted to check his movement, and he is not good - he is very good!"
"Sottsass looks great, so we do not try to complicate things. All we hope is that all goes well until this weekend and the horse will race.
"He is a colt who seems exceptional - it's up to him to prove it to us on Sunday . You know, as I often say, everything is written - and if we have to win, we will win."
Rouget hopes the adaptability of Sottsass will help him break his duck in the Arc.
"He finds it very easy to adapt to all situations," the trainer told Paris Turf.
"It's a huge advantage - unlike some horses that need a race to go perfect for them.
"Obviously, it would be better not to draw a number in the stalls on the outside. He is a horse that has caused us problems with his immaturity in the past and he is still a little fresh on the day of his races, which is normal - but you have to manage that.
"We realise that he wants to race. It's a bit tricky, but the closer we get to the start, the better he is."
With Aidan O'Brien taking out Derby winner Anthony Van Dyck, the field size still remains at 12 - after Soft Light's supplementary entry - with the final line-up announced on Thursday.
Rouget explained the late addition of Soft Light.
He said: "His owner wants to see his colours at the start of such a race - and Soft Light is a good horse, who can aim for a nice place behind the four big favourites.
"For the occasion, his owner wanted Yutaka Take (to ride). He could also have run the Prix Chaudenay on Saturday - but there is only one Arc.
"We will try not to hurt him, because he could be very good at four next year."