The visit comes a day after Valls stressed that people "fleeing war, persecution, torture, oppression, must be welcomed" and treated with "dignity" in France.
"Each asylum demand must be examined rapidly," he told members of the ruling Socialist Party gathered in the western town of La Rochelle on Sunday.
Socialist party activists had earlier observed a minute of silence in honour of more than 2,000 migrants killed since January in shipwrecks on the Mediterranean.
European Union home affairs ministers will hold emergency talks on 14 September in Brussels on the continent's escalating migration crisis, the Luxembourg government said Sunday.
Meanwhile, in Calais, ferry services resumed early Monday after protesting French seamen ended their blockade of the northern port. The demonstrations had stranded thousands of cross-Channel ferry passengers on a busy bank holiday weekend in Britain.
Sailors from the bankrupt firm Scop SeaFrance who had used lifeboats to block the busy hub will now hold talks with government officials, a senior union official told French news agency AFP.
Scop SeaFrance workers have for months been protesting against plans to sell off some of their ferries to Danish firm DFDS, a move that had led to fears of hundreds of job losses.