29 C.F.R. § 4.121
The Act, in paragraph (6) of section 7, exempts from its provisions "any employment contract providing for direct services to a Federal agency by an individual or individuals." This exemption, which applies only to an "employment contract" for "direct services," makes it clear that the Act's application to Federal contracts for services is intended to be limited to service contracts entered into with independent contractors. If a contract to furnish services (to be performed by a service employee as defined in the Act) provides that they will be furnished directly to the Federal agency by the individual under conditions or circumstances which will make him an employee of the agency in providing the contract service, the exemption applies and the contract will not be subject to the Act's provisions. The exemption does not exclude from the Act any contract for services of the kind performed by service employees which is entered into with an independent contractor whose individual services will be used in performing the contract, but as noted earlier in § 4.113 , such a contract would be outside the general coverage of the Act if only the contractor's individual services would be furnished and no service employee would in any event be used in its performance.
29 C.F.R. §4.121