The CE mark has nothing to do with light levels.
The CE Mark is a mandatory conformity symbol required for products sold in Europe (technically the "European Economic Area").
The CE mark indicates conformity to the legal requirements of the applicable European Union (EU) Directives with respect to essential requirements for safety, health, environment, and consumer protection.
It is a requirement for the "entity placing the product on the market" to ensure the product is appropriately marked and by doing so it's a declaration that the applicable conformity assessment procedures have been undertaken and the product meetings at the essential requirements.
Normally manufacturers would do this for their products as it means the importer or retailer etc doesn't have to do it making the products more attractive.
All products offered for sale anywhere within the EU must have the mark or they cannot be sold.
In the UK there are several Enforcement Bodies (depending on the product or the Directives that apply. Local Trading Standards Departments tend to cover consumer products. The Health and Safety Executive (HSE) and the Medical and Healthcare Products Regulatory Agency cover products that have specific H&S significance.
Enforcement Bodies can oblige retailers (etc) to take non-compliant products off the market, and may also impose a fine and/or imprisonment in serious cases. Its important to note that products removed from the market in one European country are also removed from the others.
BTW, the letters CE don't officially stand for anything although 'Conformity Europe' or some such French backwards language is likely it's source.