A holder of an Air Operator Certificate must be a "qualified person" majority-owned and controlled by a Mauritian registered company. As explained by the authorities during the of adherence to the OECD Declaration on International Invesmtent and Multinational Enterprises:  the definition of a "qualified person" under the Mauritius Civil Aviation Regulations 2007 (as amended) implies that the owner, lessor, lessee, any sub-lessee or operator of the aircraft be a citizen of Mauritius or a body corporate registered in Mauritius. According to the authority, only a "qualified" company, duly incorporated in Mauritius, with at least 51% shares controlled by the Mauritian nationals may be granted an Air Operator Certificate.
"Any individual, organisation or Company that wishes to operate an aircraft for the purpose of Commercial Air transport must, by law, satisfy the requirements for an Air Transport Service Licence in order to obtain an Air Operator Certificate (AOC) from the Department of Civil Aviation. The Air Operator Certificate allows you to charge to fly passengers and / or cargo on your aircraft, whether this is a jet airliner operating on a transcontinental scheduled service, a helicopter flying. This leaflet sets out the procedure that an Applicant for an AOC must follow
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7. Air Operator Certificate (AOC) ownership and nationality
All applicants for a DCA AOC must have their business registered in Mauritius and operate Mauritian-registered aircraft, with certain exceptions. The AOC must be owned by a legal entity. You will be provided with more information on these requirements at the Pre Application meeting. 
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Nationality of Ownership and Control
A holder of an AOC must be majority owned and effectively controlled by a Mauritian registered company. [...]" ("Applying for an AOC [Guide]", Department of Civil Aviation)
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"2. Interpretation
(1) In these regulations – [...] 
“qualified person” means a citizen of Mauritius or a body corporate registered in Mauritius under any enactment;
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PART II – REGISTRATION OF AIRCRAFT 
6. Registration of aircraft 
(1) No person shall, subject to paragraph (2), fly an aircraft in or over Mauritius unless it is registered in – (a) Mauritius; (b) a Contracting State; or (c) a State in relation to which there is in force an agreement between the Government of Mauritius and the Government of that State whereby an aircraft registered in that State is authorised to fly in or over Mauritius.
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7. Procedure for registration of aircraft 
(1) The Authority shall be responsible for the registration of an aircraft in Mauritius and for maintaining the register and shall record therein the particulars specified in paragraph (6) in a legible form, or a non-legible form where the recording is capable of being reproduced in a legible form. [...]
(3) Subject to paragraphs (4) and (5), an aircraft shall not be registered or continue to be registered unless the Authority is satisfied that – (a) the aircraft has not already been registered outside Mauritius, or if it has, that such registration will cease by operation of law upon the aircraft being registered in Mauritius; (b) the owner, lessor, lessee, any sub-lessee or operator of the aircraft is a qualified person; [...]
(4) (a) Where any unqualified person residing or having a place of business in Mauritius, and holding a legal or beneficial interest in an aircraft, or a share therein, applies for registration of that aircraft, the Authority may, on being satisfied that the aircraft may otherwise be properly so registered, register the aircraft in the name of that person. (b) A person referred to in subparagraph (a) shall not cause or permit the aircraft, while it is registered, to be used for the purpose of public transport or aerial work. 
(5) Where an aircraft is leased to a qualified person, the Authority may, whether or not an unqualified person is entitled as owner to a legal or beneficial interest therein, register the aircraft in the name of the lessee on being satisfied that the aircraft may otherwise be properly so registered and, subject to this regulation, the aircraft may remain so registered during the subsistence of the lease. 
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PART III – AIR OPERATOR CERTIFICATE 
11. Air operator certificate 
(1) An aircraft registered in Mauritius shall not fly for the purpose of public transport unless – (a) the operator of the aircraft is the holder of an air operator certificate; and (b) the aircraft flies in accordance with the terms of the air operator certificate. [...]" (Civil Aviation Regulations 2007 [GN 133 of 2007 – 24 September 2007] [Section 11] 


"Applying for an AOC [Guide]", Department of Civil Aviation
Civil Aviation Regulations 2007 [GN 133 of 2007 – 24 September 2007] [Section 11]
Clarifications provided by Mauritian authorities during the process of adherence to the OECD Declaration on International Invesmtent and Multinational Enterprises
[<a href="https://civil-aviation.govmu.org/Documents/Regulatory/Flights%20Operations/DCA%20-AOC%20Application%20Brochure.pdf">Guide</a>],[<a href="https://civil-aviation.govmu.org/Pages/Legislation/Regulations.aspx">Reg</a>],[<a href="n/a">Other</a>]