As lockdowns globally have been introduced and extended in response to waves of the Covid pandemic, a population of international mobile employees has emerged who work outside their home country for an extended period of time. In this time of crisis, in addition to domestic tax laws of the country where these Covid-impacted employees are working, reference should be given to the existence of a double-tax treaty. After an introduction about the mobility of workers under the Covid crisis and its tax implications (section 1) , the article begins by providing at section 2 a general overview of Art. 15 § 1 which attributes taxing power to the country where the activities are carried out as well as to the country of residence of the worker, creating a potential situation of double taxation. The article goes on at section 3 to provide an overview of the very relevant exception provided by Art. 15 § 2 which spells out the requirements under which the mobile worker is taxable only in the country of residence thereby preventing double taxation and simplifying tax compliance for the mobile worker. The article at section 4 develops a discussion the so called ‘hiring-out of labor’ which is pursued through aggressive tax structures that abuse the benefit of exclusive taxation provided by Art. 15 § 2. Then the article at section 5 looks at the treatment of directors' fees and compensations for top managers regulated by Art. 16 adopting an approach different from Art. 15, and concludes at section 6 by providing an overview of the treatment of scholarships for students and trainees under Art. 20.