Registration comes before opening
Article 6 of Regulation 852/2004 requires a food business operator to notify the competent authority of each establishment it controls, so that the establishment can be registered, and to do so before starting activity.
In Poland this is an application to the powiat sanitary inspector for the area, covering the premises and what you intend to do there. Approval rather than simple registration is required for some activities, so what you are asked for depends on your operation.
The practical point: this is not paperwork you catch up on after opening. Trading before registration is the version of this that goes badly.
HACCP is a procedure, not a document you buy
Article 5 requires food business operators to put in place, implement and maintain permanent procedures based on the HACCP principles set out in the Regulation: identify hazards, determine critical control points, establish limits and monitoring, define corrective actions, verify, and keep records proportionate to the business.
There are companies that will sell you a HACCP binder. A binder is not compliance. What an inspector looks for is evidence that the procedures are actually operating: temperature logs with real readings, cleaning records that are filled in, a corrective action recorded when something went out of range.
The Regulation explicitly allows flexibility for small businesses, including national guides to good practice, so a small café is not expected to run the same documentation as a production kitchen.
What an inspection actually looks at
Cold chain and temperature records, personal hygiene and staff health documentation, cleaning and disinfection records, pest control, waste handling, water supply, and traceability, meaning you can say where a delivery came from and where it went.
Traceability is a separate obligation under Regulation (EC) No 178/2002 and is the one small venues most often have not thought about. One step back and one step forward: your supplier invoices are usually most of the answer.
Allergen information sits alongside this but comes from different law, Regulation 1169/2011, and is covered separately.