Kim, who received three customised jackets especially for the toddler, from the designer, wrote on photo-sharing website Instagram about it, reports femalefirst.co.uk.
"Baby Balmain!!! Thank you so much @olivier_rousteing &@balmainparis for making North these one of a kind jackets!!! I'm so honoured that Northie is your little muse! Can't wait for her to wear them!!! (sic)," she wrote.
Rousteing had earlier gushed about North and said he sees the West family as representing a "new world".
Speaking about the family in March, he had said: "I don't think about them as big stars. Whether people like them or not, it's a new world and people need to embrace it. I think Kim is one of the most impressive business women I've ever met. She's got an amazing career, husband and beautiful kid. She's so powerful, but at the same time really humble with good values.
"When I was a teenager I had no reference of any mixed race couples. Kim and Kanye are one of the most famous couples in the world and the fact that Kanye is black American and Kim is white Armenian-American mix offers a great example of diversity. They are what I guess a modern couple looks like today.
"Today they are among the most talked-about people, and North is one of the most beautiful babies on the planet."