It was confirmed on Thursday that Abdelhamid Abaaoud, a Belgian of Moroccan origin linked to a series of extremist plots in Europe over the past two years, had died in a police raid on an apartment in northern Paris on Wednesday.
As debate raged about the failings that had let Abaaoud slip through the net, Valls urged France`s neighbours to "play their role properly", saying the whole Schengen system would be "called into question... if Europe does not take responsibility" for its borders.
The Schengen system allows passport-free travel between 26 countries but it has come under severe strain this year as the continent struggles with its biggest migration crisis since World War II.
More than 800,000 migrants and refugees have arrived this year and Valls said some of the Paris attackers had turned the chaos to their advantage.
"These individuals took advantage of the refugee crisis... of the chaos, perhaps, for some of them to slip in" to France, he said on the France 2 television station.
"Others were in Belgium already. And others, I must remind you, were in France."
Earlier, Interior Minister Bernard Cazeneuve said Paris had received "no information" from other European countries about Abaaoud`s arrival on the continent, despite the fact he was a known jihadist and the subject of an international arrest warrant.
Police sources said a tip-off from Moroccan intelligence had helped track 28-year-old Abaaoud to the building where he died on Wednesday along with a woman thought to be his cousin, who detonated an explosives vest.
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