I see PSG team is considered as favorite on most of the gambling sites. Even Google prediction has PSG team ahead. I don't know on what statistics PSG team is considered as favorite.
PSG and Inter Milan are both very strong. Inter Milan gave full effort in Champions League matches this season. And because of this, the team failed to win both Coppa Italia and Serie A titles. Milan was eliminated in the semi-finals of Coppa Italia and lost Serie A title due to losing points in the last match of Serie A. Inter Milan failed to win at the last minute.
Inter Milan qualified for Champions League final by defeating Munich and Barcelona. I consider PSG and Inter Milan's chances of winning are equal so far. Both have strong squads and experienced coaches.
I think it is so because everyone has concluded that PSG are more hungry for the title than Inter Milan and will want to win at all cost and given that this season many teams winning titles are winning for the first time and breaking droughts it is expected that PSG will break their Champions League drought too lol.