The CE Marking is a conformity marking consisting of the letters "CE". The CE Marking applies to products regulated by certain European health, safety and environmental protection legislation. The CE Marking is obligatory for products it applies to: the manufacturer affixes the marking in order to be allowed to sell his product in the European market.
The CE it refers to the safety rather than to the quality of a product. Second, CE Marking is mandatory for the product it applies to, whereas most quality markings are voluntary.