No, it is not. 

A Certificate of Conformity, a.k.a. Certificate of Compliance, only shows that an independent test laboratory has tested your product and verified that it fulfils the requirements of one or several CE directives.

To market your product in the EU, you must compile a technical file and draw up and sign an EU Declaration of Conformity. Only by doing so you can show that you have taken all the actions required by the applicable EU legislation and assume full responsibility for the product's compliance status.