Speaking to parliament, Valls said: "This request... is balanced, positive. It shows a real willingness to move forward and reform."
The PM praised an "important step which will allow for negotiations."
Valls, who has repeatedly shown a conciliatory tone towards Athens, said once again that "everything must be done to keep Greece in the euro".
In his speech to MPs, Valls said a vote would take place in parliament in the event that a deal was reached between Greece's creditors and the government in Athens.
Valls said that keeping Greece in the eurozone was a "geopolitical issue of the highest importance".
"An exit would definitely cause a drop in revenues, exploding import costs, including for basic goods, social and political consequences that none of us are able to predict. Is that what we want for the Greek people?
"Is that the image of Europe we want to give to the world?"
Earlier it emerged that France's exposure to a Greek debt default would total €65 billion (about $72 billion), according to a report by the Senate's finance commission.
"Our country's total exposure to a possible Greek default represents around €65 billion, well above the €40 billion usually cited," Senator Alberic de Montgolfier said in a statement accompanying a report he delivered to France's upper house of parliament.
The estimate was disclosed as members of the French government, including finance minister Michel Sapin, have expressed a willingness to consider reducing Greece's crushing debt load of over 320 billion euros as part of a new rescue programme seeking to avert a Greek default and probable exit from the eurozone.
Last week Sapin noted that "the debt question isn't taboo" in seeking a last-minute bailout accord with Athens.
Eurozone leaders have ordered Greece to submit detailed reform proposals towards a new deal by Thursday following the Greek rejection of terms of the previous bailout accord in a referendum Sunday.
Greece on Wednesday pledged to make "credible" reforms including measures related to tax and pensions in return for a three-year eurozone loan. All 28 European Union leaders will examine the plans on Sunday in a make-or-break summit.