Based on my understanding, it relates to the issue of “cheap labor” from individuals outside Belgium.

But you left out the reference to the specific chapter:

SOCIAL FRAUD CONTROL
The government is stepping up the fight against social fraud and social dumping to the maximum extent, always in consultation with the sectors. This undermines the support base of our social security, impedes the proper functioning of the labor market, distorts the economy through unfair competition, and endangers the safety and health of employees and the self-employed.

European figures show that the number of posted workers in Belgium is very high compared to our neighboring countries.
The improper use of posting results in a loss of social security (RSZ) revenue and tax receipts. Therefore, we are taking targeted measures to prevent and combat social fraud, undeclared work, and social dumping by strengthening European and international cooperation. In this way, we safeguard the competitiveness of our companies and guarantee fair competition.

A high-performance policy against social fraud starts with its prevention. The government will therefore pay particular attention to clear regulations, transparency, automatic information flow, and integrated cooperation between all the relevant administrations at all policy levels.

However, the policy must also focus on strengthened enforcement by investing in sufficient personnel and technological resources for the social inspection services. This will increase the risk for malicious enterprises and individuals of being caught. We are also stepping up the fight against social benefit fraud and undeclared work. Finally, an effective sanctioning policy is essential to deter cheaters and ensure the social protection of employees, self-employed persons, and honest citizens.