Difference between contract workers & workers through outsourcing?

Sir,
From what you say, it appears that these contract workers are working in your establishment. In such a case, and only in such a case, is Shri Saikumar correct: it does not matter if you call this outsourcing or contract labour. So long as such persons are working in your establishment, they come within the purview of Contract labour.
From a HR angle, it may make sense for you to do what you seek. It will reduce the burden on the HR staff to deal with the approvals (why would you take approvals if the exiting employee is a contract worker?), dealing with the exit of such employees and recruiting fresh ones on exit.

I would like to know from our friend Sarwin whether the global mfg company is situated in France while its various departments/units located elsewhere.

Dear Friend,
Contract Workers and Outsource Workers same and their engagement & disengagement is administrated under rules frame under CL(R&A) Act. The meaning of Outsource is nothing but to do the work by a separate agency without involvement of principal employer as an entity.
The distinction of contract & outsource emerged to see the thing in a different angle i.e. core and non-core activity of the PE. The Outsource work is of perennial nature carried out by a third party instead of principal employer with own supervision. Whereas the work of time bound & non-core activity is done by the contractor.

There is a big difference between the worker of a third party outsourced service provider and a contract worker. And the difference is as:
Contract Worker - A "contract worke"r is employed through a "contractor" who possess a due lisence of supply of contract worker. Here the ultimate employer is called "Principle employer". The entire process of employment of contract worker is regulated by The Contract Labor Abolition and Regulation Act 1971, that defines "Contract Labor", "Contractor" and "Principle Employer". As per the Act, the Principle employer has secondary liability towards the payment of wages and dues, as well as Welfare amenities.
Third Party Worker - Is a worker who works on behalf of a third party service provider who has been contracted to provide an outsourced service. Please note that here the third party service provider is not a "Contractor providing contract worker". Also the worker is NOT a "contractra worker" as also the ultimate employer is NOT the "principle Employer". All because the entire process in not regulated by the Contract Labor Act, but is a result of a service level agreement between the client and the service provider.
Prof. Neeraj Kataria
University of Petroleum & Energy Studies