Employees who work for Russian companies remotely under both labor contracts and civil-law contracts (such as civil-law agreements) will pay a personal income tax (PIT) at a rate of 13% (or 15% for high incomes), regardless of their tax residency.
As stated in the document, the income received as compensation and other payments for remote work performed under an agreement with a Russian organization – employer is considered income from sources in Russia and is subject to the tax rate applicable to taxpayers who are not tax residents of Russia, in the amounts established for taxpayers who are tax residents of the Russian Federation.