After promising to overcome the ideological divisions that have long hampered French policymaking, Mr Macron has a delicate balancing act to pull off.
Several ministers, including Le Maire, have said they will stand in the parliamentary election, and Philippe confirmed that they would have to quit the government if they lost.
But Merkel papered over the differences, saying that "from the German point of view, it's possible to change the treaty if it makes sense".
(AP Photo/Christophe Ena). New French Interior Minister Gerard Collomb arrives for the first weekly cabinet meeting under new French President Emmanuel Macron, Thursday, May 18, 2017 at the Elysee Palace in Paris.
Macron was greeted with full military honors upon his arrival, with hundreds of onlookers waving European flags and shouting his name.
Macron sought to allay concerns among German conservatives that he could push for the eurozone to develop into a "transfer union" in which Germany is asked to bankroll other states.
Berlin hopes to gain new momentum and support from Paris for reforms of the European Union in general, but particularly for the Eurozone.
Visiting Berlin on Monday, Macron "did not push for major, ambitious reforms (of the EU) because he knows the chancellor can not deliver until the elections in September", said Judy Dempsey of the Carnegie Europe think-tank.
Meanwhile, Philippe said hours after his appointment on May 15 that he chose to accept the job Macron offered him because France is in a "unique situation".
Emmanuel Macron, France's president, has announced his cabinet.
On Tuesday, he and Philippe were finalising a government which Macron says will supersede France's entrenched left-right divide and breathe new life into the country's jaded political landscape.
Mr Philippe is a member of the mainstream-right Republicans party and could possibly attract other Republicans to Mr Macron's cause, as the centrist president works to piece together a majority in parliament to pass his promised economic reforms.
Taking over from outgoing prime minister Bernard Cazeneuve during a short ceremony, Philippe described himself as "a man of the right" who was driven by "the greater good".
Some in the party have argued in favour of an alliance with Macron.
But not everyone was pleased with the Philippe announcement.
Faced with the rise of populism and Brexit, the arrival of Macron to the presidency, (but even more so the elimination of Europhobic candidate for the extreme right candidate Marine Le Pen), has undeniably provoked relief in Berlin, as in many European capitals.
Defeated by a Macron landslide, she denounced what she predicted would be a continuation of old policies, including "austerity, submission to Brussels, massive immigration".