CE-marking was made mandatory within the European Union (EU) for certain products, to ensure that only safe products were put on the market throughout the EU.
If a product is CE-compliant, that product meets essential EU safety standards. These are defined in the relevant directives.
It is not a mark to indicate any particular product quality. CE-marking states that all the European directives applicable to this product have been met.
[... more information on European directives]