Caitlyn Jenner and Lamar Odom were also with the family in the audience.
"Yeezy vibes," the star captioned a photo of her new look.
"The fam all dressed in exclusive Balmain for Yeezy pieces! Kanye flew to Paris a week ago and @olivier_rousteing made it happen in 5 days!!!"
Kardashian previously went blonde during Paris Fashion Week in spring 2015.
West's event introduced his new Yeezy collection and served as a release party for his seventh studio album, The Life of Pablo, which drops Friday.
Kardashian and West welcomed North in June 2013 and married the next year.
The reality star discussed the difficulties of parenting two children in a blog post Wednesday, saying she was "up at 4 a.m., pumping and delirious."
"My mom would always say, about having kids: 'One is like one, and two are like twenty.' I never really understood that until now," she wrote. "Of course, I expected it to be different but, wow, it really is so hard! When I had North, all I did was feed and sleep. This time around, I get no sleep."
"Every waking second that I'm not with the baby, I'm with North," she shared. "I actually think the harder parts aren't with the newborn but with the toddler! I feel like I go into overdrive to give my daughter attention and make her feel loved."
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