Civil society groups and individuals in Angola have welcomed the sacking of Ms Isabel dos Santos as head of state-owned oil firm Sonangol.
The eldest daughter of former President José Eduardo dos Santos was Wednesday replaced as the Sonangol board chair.
A decree by President José Eduardo named Mr Carlos Saturnino the new chairman of the state corporation.
"President João Lourenço has restored constitutional legality against an act of nepotism made by José Eduardo dos Santos," political analyst Fernando Macedo told VOA Radio.
"The sacking means the restoration of ethics in governance," said Mr Elias Isaac of the Open Society Organisation in Angola.
Mr Isaac said the dos Santos family had inordinately dominated the Angolan society.
President dos Santos in 2013 also appointed his eldest son, Mr José Filomeno dos Santos, to head the strategic $5 billion Angolan investment sovereign fund, created in October 2012.
Former Prime Minister Marcolino Moco said President Lourenço was cracking down against the scandalous appointments by his predecessor.
Ms Isabel dos Santos was appointed by her father to chair the Sonangol board of directors in June 2016.
Twelve lawyers challenged the appointment and petitioned the Attorney-General Office to annul it for going against the public probity laws.
"The law says a public agent must not nominate or allow nominations of his wife or his first degree relatives," the lawyers argued.
Last year, a court summoned President dos Santos and Isabel over the latter's appointment to the public oil company.
Ms Isabel dos Santos's assets in Angola include a 25 per cent stake in Unitel, one of the country's two mobile phone networks and another 25 per cent stake in Banco Internacional de Credito (BIC).
Angola is the second-largest producer of crude in Africa and was regularly cited as one of the continent's fastest growing economies.
However, since the beginning of 2015, the southern African country has faced a serious economic crisis, occasioned by the oil price depression on the international market.
Angola relies on crude exports for two-thirds of tax revenue, and 95 per cent of its foreign currency receipts.
Critics say the billions of oil dollars flowing in had not benefited the ordinary people, and had only succeeded in creating an elite few.
According to the United Nations, the oil sector represents 97 per cent of Angola's exports and 80 per cent of public revenues and employs one per cent of the population who with less than $2 per day.