Gabriel said that if countries in eastern Europe and elsewhere continued to resist accepting their fair share of refugees, the bloc's open border regime, known as Schengen, would be at risk.
But business was up at the Schengen Bar next to the departures lounge.
Populist parties elsewhere in Europe are making similar demands, amid widespread fears that migrant workers are taking advantage of Schengen at a time of economic hardship.
Asked about border controls inside Europe, which many fear put the passport-free Schengen zone at risk, Valls said the concept of Europe was in jeopardy.
She reiterated her longstanding call for France to withdraw, unilaterally and at once, from the Schengen Agreement, which allows for open borders within the extended European community, but that was hardly newsworthy.
Asked about border controls inside Europe, which many fear put the Schengen zone at risk, Valls said: "If Europe is not capable of protecting its own borders, it's the very idea of Europe that will be questioned".
In an incident EU leaders will hope symbolised nothing very much, two visitors and an attendant escaped shocked but unharmed after a 40sq m section of suspended ceiling at the European Museum in Schengen, Luxembourg, collapsed under the weight of rainwater that had seeped in.
If Greece fails to pull through, then it may be looking at expulsion from the Schengen area in three months.
The two countries are being kept out of the Schengen zone largely at the behest of Germany and France, suspicious of corruption and lax border controls.The euro zone and the Schengen area depend on trust: that each member will run sound public finances, and that each will control its borders.
