PARIS — At least the river is receding. After days of torrential rain, with the rising brown waters of the Seine forcing artwork at the Louvre to be moved to higher floors, there was continued reprieve on Thursday. Thick morning clouds gave way to blue skies, and the cobblestone banks were baked nearly dry. On the long list of worries about the European Championships, one concern could be crossed off: Paris won’t be underwater.

There are still strikes and the threats of more — from garbage collectors, train drivers, Air France pilots — with protests planned for several days over the monthlong tournament. There seemed to be more bags of trash than tourists in the streets before Friday’s opening match between the anxious hosts and Romania at the Stade de France.

But terrorism remains the consuming topic of conversation in the discomforting quiet of the capital. Since attacks here in November, which included a trio of detonations outside a friendly between France and Germany, Paris has been gripped by a kind of nervy defiance. People are returning to sidewalk cafes and the trains are filling with commuters when they’re running, but this city still doesn’t feel as it once did. It’s like attending a party where everybody is pretending to have a better time than they are. Even on the eve of one of football’s grand tournaments, the line between anticipation and foreboding remains blurry.

“You mustn’t try to play the game before it actually happens,” French coach Didier Deschamps said on Thursday. He was talking about the match against Romania and weathering the considerable accompanying pressures of such a moment. But he might also have been talking about how to resist forces far larger.

Normally the preoccupying thought would be about who might win the Euros: whether France, hosting their first major tournament since their glorious 1998 World Cup campaign, can claim a trophy on home soil once again; whether Germany, after their clinical capture of the World Cup in Brazil, can be stopped; whether one of the smaller sides in this year’s expanded format, Iceland or Wales perhaps, can record a historic upset.

In Paris, at least, a less optimistic imagination is on clearer display. Organizers have promised a security presence that is intensive and yet not alarming, a difficult combination to achieve. The Stade de France has been ringed with concentric circles of tall fences and metal detectors, while 90,000 security personnel have been dispatched to the 10 host venues. But police exercises that included mock victims laid out in plazas didn’t really do anything to dull this city’s edge. There was a whisper of relief when the French Open concluded without incident, but now comes the Euros and the Tour de France. In their crowds and chaos, there is also the grim acceptance that if terrorists want to murder innocent people, they will have no shortage of opportunity.

Maybe as the tournament goes on, and maybe in the other host cities — smaller, less recently scarred — there will be a greater sense of occasion. Maybe after Friday’s opener, there will be a collective calming of nerves.

Or maybe this is just how it’s going to be from now on.

It’s not nice to think so. We know we’ll have lost something important if football and everything beautiful it represents is cast in a permanent shadow. So we remind ourselves of all the bromides against fear, that changing our lives and how we choose to live them is what terrorists want, that the odds of being caught in an attack are infinitely small, that for every bomb that goes off there are dozens of plots that are foiled.

In the end, for all our preparations and statistics, right now all any of us here has is hope. Hope that nothing bad happens, and if it does, that it is not as bad as it might have been, and that if it happens to us, we turned left instead of right, or we caught the train before or after, or we were standing at a slightly different spot at a slightly different time. Hope that physics and circumstance somehow spare us. Hope that the sun comes out and beats back the floods and we see something of our old self surface again, coming up for air.