Yes. You will need at least three "regular" clients. 

They (your client) are the ones who will take the hit in case of an external audit and as social charges may be requested to be paid also retroactively, they should most likely be made aware of the legal risk involved.     

Thanks Eva,

This is helpful. I am the employer at risk btw

OK well and in which case you will most likely wish to:

a) re-negotiate the (presumably) present corporate consultancy/services agreement into not being a full-time one (at least not on a permanent basis); or

b) terminate such and enter into an employment one instead for the person in the servicesco. presently providing said consultancy services to you. Calculate on increased costs for all relevant social charges and insurances incl. of approximately 28% (rough ball-part figure-  nota bene). 

I agree with what has been stated in the case of a self-employed service provider

However if it is the “société en commandite par actions” as legal entity which invoices the services, then the person providing the services is supposed to be employed by this “société en commandite par actions” whereby all obligations relevant for an employer should be covered.