10. Is there a ban on donations from corporations with government contracts to candidates?

Article 8 'Prohibited Funding- 1 - Political parties may not receive anonymous donations or receive donations or loans of a pecuniary or in kind nature of national or foreign legal persons, except as provided in the following number.' 

Article 8.3 ‘- It is specifically forbidden to political parties:
a) Acquiring goods or services at prices lower than those practiced in the market;
b) Receive payments of goods or services rendered by them at prices manifestly above their market value;
c) Receive or accept any indirect contributions or donations that result in the payment by third parties of expenses that they enjoy.’

Source  Decree of the Assembly of the Republic No. 194 / XIII: Political Funding -Alteration to the Law approved Friday, March 9, 2018