According to ANSSI the intermediate CA certificate was used in a commercial device, on a private network, to inspect encrypted traffic with the knowledge of the users on that network. However, in response, Google updated Chrome’s certificate revocation metadata immediately to block that intermediate CA, and then alerted ANSSI and other browser vendors.
Read more here- http://googleonlinesecurity.blogspot.com.au/2013/12/further-improving-digital-certificate.html