Some 46,000 undocumented immigrants were given papers to stay, 10,000 more than the previous year, the figures, published Friday, showed.
They are the first official review of government migration policy since François Hollande came to power in May 2012.
Valls explained these figures by a drop in assisted returns, especially of Roma from eastern Europe, and accused the government of former president Nicolas Sarkozy of massaging the statistics by paying immigrants to leave France between 2006 and 2011.
The assisted returns policy benefited Roma but was not efficient as immigrants shortly came back to France, Valls argued.
Scrapping it in February 2013 has made savings of 11 million euros, he claimed.
Valls, who tried to combine tough talk on immigration with a more humane stance, on Friday said that naturalisations have risen 14 per cent rise - a logical integration process according to the government, an enlargement of the left-wing electorate for his opponents.
Eric Ciotti, an MP from Sarkozy's UMP, accused the government of "laxism", claiming that it had "opened the doors to immigration", while UMP security spokesperson Michèle Tarabot claimed thtere had been an "explosion" of regularisations of undocumented immigrants.
According to the interior ministry, there are about 300,000 to 400, 000 illegal immigrants in France.