It's after the resignation of Edouard Philippe who has been in the post for three years.
Mr Castex, 55, is relatively unknown in France, although he is a senior civil servant.
The new Prime Minister has been a key player in the government's response to the Covid-19 pandemic.
Trump adds seven countries to full travel ban list
President Donald Trump has expanded a list of countries subject to a full travel ban on Tuesday, prohibiting citizens from an additional seven countries, including passports from Syria and Palestine, from entering the United States.
Indian parliament votes to allow private firms in nuclear power sector
The lower house of Indian parliament on Wednesday voted in favour of an atomic energy bill that will allow private participation in the country's nuclear power sector.
Doctors in England start five-day walkout during flu surge
Doctors in England began a five-day strike on Wednesday over pay and working conditions during a surge in flu cases and with no end in sight to an increasingly bitter dispute with the government.
Israeli settler kills 16-year-old Palestinian in West Bank, mayor says
An Israeli settler shot dead a 16-year-old Palestinian in the town of Tuqu' on Tuesday after the funeral of another teenager, the town's mayor said.
Paris' Louvre reopens partially but staff vote to extend strike
France's Louvre museum in Paris partially reopened on Wednesday despite its staff unanimously voting to extend a strike they began on Monday over pay and working conditions.
For one morning only, you could host the UAE’s biggest radio show, The Kris Fade Show - live across the nation.
The legendary Craig David joins The Kris Fade Show for an unforgettable chat!
The boys tried their 'pick up' lines on Mais Vault and things did not go according to plan...
It arrived: The UAE's First Mega Music Festival at Expo City Dubai!
