|Reality TV star Kim Kardashian was robbed at gunpoint in Paris of $10 million worth of jewellery|
"You cannot display your wealth and then be surprised that some people want to share it with you," the designer told reporters after his Chanel show.
Lagerfeld had written Kardashian a note on Monday saying: "Dearest Kim, we are all with you", after she was tied up and robbed at a luxury apartment in Paris.
But he criticised the celebrity for showing off her jewellery to her more than 100 million social media followers.
"If you're that famous and you put all your jewellery on the net, you go to hotels where nobody can come near to the room," he said.
Kardashian tweeted a picture last week of a diamond ring worth around four million euros ($4.5 million) which police said had been stolen in the early morning raid along with five million euros worth of other jewellery.
"I think it's a very bad thing for Paris but I don't understand why she was in a hotel with no security," Lagerfeld said of the robbery, which made headlines across the world.
The multi-millionaire mother of two and wife of the US rap superstar Kanye West had been in Paris for fashion week, where she was a front row guest at Balenciaga and Givenchy on Sunday.
The outspoken 83-year-old German-born designer and photographer, who is known as "the kaiser" for his mastery of the fashion world, has previously been complimentary about Kardashian and her family.
He even did a photo shoot with her this summer for the American magazine Harper's Bazaar in which he had West taking a picture with his mobile phone of Kardashian draped across a bed.
Kardashian's half sister Kendall Jenner also modelled for him in Chanel's Paris haute couture show last year.
Her mother Kris Jenner is also known to be a client of Chanel.
Lagerfeld has previously said that "Kim's contribution to beauty and fashion is the fact that you don't have to be super slim and very tall to be beautiful".
"I like her mother a lot and I adore her little half-sister Kendall. I don't know the rest of this astonishing family," he told the celebrity news site Page Six.