Before placing a substance or mixture on the market, you must meet the following requirements:

1. Classify, label and package the substances and mixtures in compliance with Article 4 and Titles II, III and IV of the CLP regulation.
2. Classify substances that have not been placed on the market but that are required to be registered or notified in accordance with Article 6, 9, 17 or 18 of the REACH regulation, in compliance with Article 4 and Title II (Articles 5-14) of the CLP regulation.  
3. If a substance is being placed on the market, then notify the classification and labelling to ECHA (European Chemicals Agency) so that it can be written down in the inventory in compliance with Art. 40 of the CLP regulations.The substances placed on the market after 1st December 2010 must be notified within one month after being placed on the market.
Substances placed on the market before this date, must already have been notified.
Note: The substances registered under REACH are already included in the inventory. Therefore they do not need to be notified.
You will find more information about the notification procedure of a substance in the inventory on the ECHA website.
4. Take all suitable measures to know about the new scientific or technical information likely to modify the classification and, if required, get your product re-assessed.
5. Update the information for classification and labelling at the earliest when the new hazard is more serious or when new labelling elements are required.
On the other hand, an 18-month period is granted for updating the labelling if changes to be made do not pertain to a more serious hazard (for example lowering of classification) or to new labelling elements.
6. If you have new information about changes in an harmonised classification and labelling of a substance, you must submit a proposal to the competent authority of a Member State where the substance has been placed on the market.
In case of Belgium, the competent authority is the Risk Management department (reach@health.fgov.be).
7. Keep the information used for classifying and labelling for 10 years after the last supply (i.e. sale and discontinuation for free), in compliance with the CLP regulation.

See more information about classification, packaging and labelling.
Specific requirements exist for manufacturers and importers of some specific article of consumption.