The extra French lessons are part of immigration reforms under President Emmanuel Macron intended to balance swifter deportation of rejected asylum seekers with better support for those allowed to stay.
The lessons will rise to 600 hours for new arrivals who are particularly struggling to learn the language, Philippe said after the first meeting of an inter-ministerial committee set up to work on the integration question.
Philippe said French efforts to integrate migrants had until now "lacked ambition", adding that the country needed a policy "worthy of our republic for all those to whom we give the right to stay in France".
He did not say how much the scheme would cost.
Extra language lessons were proposed as part of dozens of measures in a report by Aurelien Tache, a lawmaker from Macron's Republic on the Move (LREM) party, which he estimated would cost a total 607 million euros.
France will also double to 24 hours the "civic training" courses given to refugees, designed to explain French values as well as practicalities such as how to obtain work, healthcare and housing.
Many recent arrivals find the barrage of information in the current 12-hour course overwhelming, but Philippe said an understanding of fundamental French values such as liberty, fraternity and equality was "not an option but an obligation".
Immigrant parents will also be offered free childcare during their French lessons, while those turning 18 will have access to a new 500-euro "culture pass" for young people to spend on museum trips and other cultural activities.
Philippe said the measures, which will also include better help for immigrants in finding jobs, were an investment in France's "national and social cohesion".
France received a record 100,000 asylum applications last year and offered refugee status to around 30,000 people, while deporting 14,900.
Though the notorious "Jungle" camp in Calais was cleared in 2016, increasing numbers of migrants have been camping along the canals in Paris in recent months, many from Afghanistan, Eritrea and Sudan.
On Monday police began evacuating around 1,000 migrants from two makeshift camps, five days after another 1,000 were taken to temporary lodgings.