This here is the problem for most of EU countries.
We Dutch are proud how easy it is to do business here. Maybe, compared to some other countries. But starting a BV here and 1 month later finding a representative of a trade union (metal sector, which somehow semiconductors fall under together with car garages, petrol stations, steel factories..) and asking me to come to their office in person to explain what we do, and calculate how much their cut will be was weird at first. Of course being extremely busy with actual business, I forgot, and got a letter with an 100k Euros invoice attached. Apparently they assumed 15 employees with 45k gross salary, and thought this is a fair trade union contribution! When I didn't respond to that, while discussing it with our lawyers, they sent a fine over this invoice which made it 140k. This is all within 3-4 months of registering mind you! At the end the lawyers handled that, but yeah, what the hell..
> finding a representative of a trade union
> how much their cut will be
Did you have any employees yet? I guess so. Isn't it the employees' responsibility pay for their union membership?
These trade unions are notorious for that. I worked as a labor legal advisor and especially the unions for temporary employment agency start 'barking' and demand loads of money (even from years back). Sometimes it's not even clear which union is applicable.
You probably have all the info right now, but make sure everything is 'in line'. I mean, have your company codes at the tax authority match the applicable union match the actual things that your company does. Depending on the jobs of the employees, it might be smart to split the company into multiple legal entities.
All in all you can be happy that this happened within a couple of months. Finding this out when you're years underway and then having to pay millions... I've seen plenty of these cases.
Want to start a business in The Netherlands? Make sure to do a 'CAO check' first, think about how to structure your company (one entity? multiple entities? what job goes where?), and do these checks again once you pivot or make certain changes to the actual work that your company does.
The rationale for this is also pretty simple: somebody got to pay for all this nice social security. They say it's part of the risk of being an entrepreneur.