If you want to market a product, it is important to find out whether your product has to meet certain quality requirements and what rights are attached to selling the product.
Quality requirements are laid down in agreements (standards) that specify the requirements and conditions a product must meet.
CE marking indicates that a product complies with the applicable rules within Europe. CE-marked products can be freely traded in the EU.
A patent is an exclusive right to industrially make or sell a product. In Dutch it's called an octrooi or patent.