What should travelers expect in the wake of terrorist attacks such as those that shocked Paris last week?

Time will make the scars easier to bear, but the mood in Paris and the logistics for travelers heading there will change for the foreseeable future. Eventually after 9/11 Americans began to look at airplanes almost the same way again, and sooner or later Parisians, too, will return to their cafes and concert halls with the most of their famous ease and enjoyment of life.

But one look at the TSA shows how impossible it is for a generation to completely forget a major act of terror.

In the short term life will change and travelers to France should prepare to visit a conflict zone.

Signs will show up, first and foremost on the streets. For the foreseeable future the City of Light is under siege and will crawl with heavily armed police. Although trains (metro and national) are running as normal and taxis have not left the streets, build in extra time and prepare for checkpoints and bag searches.

It’s also important for travelers to understand the reason cities militarize in the wake of a terrorist attack. Many people treat it as security theater, soldiers posturing against large guns when the attack has already happened.

Unfortunately, said Roger Cressey, a former member of the National Security Council and a Partner with Liberty Group Ventures, cops have to treat the possibility of multiple attacks as an all-too-realistic possibility. In many ways the wake of an attack, with a city focused on tending to its wounded and burying the dead, would be the perfect time for a follow up or copycat.

“Law enforcement doesn’t have the luxury of making the assumption that there won’t be additional attacks,” he said. “I mean, can you imagine the first politician to go after a commissioner of the police who said, ‘Oh yeah I, thought this was one and done...’?”

He added that it's important for authorities to ignore the people who are dismissive of some of these steps. "They’re not the people that law enforcement is worried about," he said." It’s more when you don’t have specific information about specific individuals and their intent you have to cast a very broad net.”

In fact, life after an attack moves more slowly in general, and by design. Lines, checkpoints, holdups all allow law enforcement to buy time, slow down and process threats.

For visitors and residents of Paris, and likely many other French cities, this will create both inconvenience and costs. While both Charles de Gaulle and Orly airports are open, the airports have warned travelers to expect delays due to heightened security.

Many airlines are allowing passengers until the 22nd of November to change itineraries into or out of Paris at no charge.

Even as they create problems, checkpoints exist because they work. Random checks create an unpredictable obstacle for terrorists, who depend upon dependability to pull off their attacks. Even the possibility of a bag search at the metro station is enough to force an attacker to choose a new target.

“It’s akin to the TSA,” said Kiersten Todt, president of Liberty Group Ventures and a former Congressional staff member who helped develop the Department of Homeland Security. “You’re going to go where you have the least amount of pushback and resistance.”

Even when an attack continues, checkpoints tend to minimize and contain the violence.

“If you look at where the least effective attempt was in Paris, it was the stadium,” Todt said, speaking of where attackers had to detonate their bombs prematurely due to security.

Perhaps the biggest challenge to responding after an attack is dealing with the unknown. Unlike on television, there is no confession against the clock, rarely any such thing as perfect knowledge. Instead, law enforcement makes the best guesses it can and tries to secure the most vulnerable targets.

That will mean greater security outside of landmarks, tourist attractions and transportation hubs, which all currently remain open.

Watching armed soldiers patrol the streets is a world bending feeling for many westerners. Police and soldiers carrying assault rifles blend poorly into the background of our lives and, no matter how official their capacity, it’s almost impossible even in a romantic city to walk by someone equipped for the battle and not feel a sense of menace.

Even if he’s on our side, it seems to scream that the fight has come home. It’s darkly ironic, then, that those soldiers serve exactly the opposite purpose.

If the first goal of security in a conflict or post-conflict zone is to prevent another attack, Todt and Cressey said, the second is to help civilians -- both city denizens and visitors -- regain a sense of normalcy. Heavy security in the streets may seem intimidating, but they also provide some sense of reassurance that it’s safe for people to leave their homes and return to public spaces.

“You don’t want that type of environment two, three days after an event,” Todt said. “The appearance of safety and security [is] psychologically very important for the citizens.”

Traveling through a conflict zone requires extra care, time and expense. At the end of the day, however, Paris is not a conflict zone. It’s a city getting back up on its feet.

Visiting it will incur delays, hassle and probably some extra expense. Go anyway.