Despite finishing top of their group, Manchester City were handed arguably the toughest fixture when they drew Real Madrid in the knockout phase. They ended up runners-up in their own group behind Paris Saint-Germain.
Los Blancos have never lost a knockout game in the competition under manager Zinedine Zidane, who won the trophy three years in a row before leaving his role at the Estadio Santiago Bernabeu. Zidane returned as boss in March last year.
"I wanted City to get Lyon or some club like that, but Real Madrid is going to be a tough game, a very, very tough game," Toure - who now plays for Chinese Super League side Qingdao Huanghai - told Omnisport, via AS.
"Real Madrid could knock us straight out. They could, they really could, because we expect Real Madrid to be in the quarter-finals, the semi-finals and now they face City.
"I'm a little scared to be honest."
Man City face Madrid at the Bernabeu in the first-leg on February 26, before the return leg at the Etihad Stadium on March 17.
When La Liga leaders were eliminated by Ajax at the last-16 stage of the Champions League last season, they sacked head coach Santiago Solari and reappointed Zidane - just 10 months after he left the club.
The Frenchman has overseen a 15-game unbeaten run in the Spanish top flight to take the 13-time European winners to the top of the table.
