Greetings,
A company needs to send 12 employees to Turkey for one year to help work on a project that the company has been contracted for by a Turkish company.

Are work permits/visas and residency permits required? Are there separate applications for work permits, work visas and residence permits?

Is it a problem that their employer is not Turkish, though the company that the employer has the contract for the project with is Turkish.

When would this exemption apply:
Employment of foreigners in foreign capital investments
Article 23- Foreigners, who are requested to be employed in companies and establishments founded in the framework of the Law of Foreign Capital Stimulation number 6224, may be employed by the work permit issued by the Ministry in the framework of the procedures and principles to be determined by the regulations to be released jointly with the Underseceratry’s Department of Treasury.

There is also the following exemption (source unknown):
"Foreigners who will work in national or international projects that will be implemented by consortiums or in compliance with bilateral or multilateral agreements Turkey is party to, or in international organizations, with the condition that their stay should not exceed one year."

Finally, what are the penalties for working in Turkey without a work permit?

Any explanations/answers to the above would be greatly appreciated.