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Building a better Paris in Assassin's Creed Unity

Historical accuracy meets game design

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This story was originally published on October 31st, 2014. But in the wake of the tragic fire at the Notre Dame cathedral in Paris earlier this week, we’ve decided to re-publish it, to provide a timely look at how the iconic building influenced various facets of our culture, including video games. Ubisoft’s also giving away free copies of the game on PC through April 25th.

It took 182 years to build the Notre Dame Cathedral in Paris, starting with the first bricks in 1163. For Caroline Miousse, a level artist on Assassin's Creed Unity, building a virtual likeness centuries later took considerably less time — she spent around two years modelling the landmark inside and out. "I made some other stuff in the game," she says, "but 80 percent of my time was spent on the Notre Dame."

Like previous games in the series, the star of the next Assassin's Creed is its setting. This time around the game takes place in just one city, Paris, during the French Revolution (and also, somehow, during World War II). It's also the first game in the franchise built for the Xbox One and PlayStation 4; last year's Black Flag was a sort of bridge game, launching on both last and current-gen consoles.

ACU is the most detailed city the team at Ubisoft Montreal has built to date. It's both huge and dense, and even features plentiful interior locations and underground tunnels to explore. The streets are teeming with people — upwards of 10,000 Parisians can be featured on screen at a time. Great pains were made to ensure the city in the game was true to the one that existed in 1789, but much was also changed.

"It's a better Paris than the actual Paris for gameplay," says world level design director Nicolas Guerin. "We have to build a game playground first, and on top of that make a cool city that's visually striking and historically accurate as well."

Assassin’s Creed Unity
Assassin’s Creed Unity
Notre-Dame Cathedral in Paris

Ensuring that base level of historical accuracy involves a lot of research. For Guerin, whose job involved, among other things, the layout and design of the city, that meant a lot of maps. Over the course of three months or so he says he looked at more than 150 maps of the city, which provided information on the layout of Paris at the time, and how it changed over the years. Having so much information to work with was a big change compared to past games — for cities like Constantinople, the setting of Assassin’s Creed Revelations, maps and historical texts were a lot harder to find. Many had been destroyed over the years, and even those that were available were in Turkish, making it more challenging to parse.

Assassin’s Creed Unity
Assassin’s Creed Unity


”We were lucky with Paris because it’s quite a well documented city,” Guerin explains. “Many of us are French or Quebecers, so it was easy to get the material right from the beginning.” Ubisoft also employs several staff historians to help dig up any extra details the development team might need.

Those maps also helped determine one of the key aspects of the city that needed to be changed. Paris is incredibly dense, with cramped streets and tightly-packed buildings, which conflicted somewhat with Assassin’s Creed’s free-roaming movement. So in order to make Paris more of a playground, the team used a process called “radial scale” to change its layout. It’s a simple concept: in the center of the city it’s essentially a one-to-one recreation, but the further you move from Paris’ core, the more spread out things get. Key landmarks are all in the right place so that it still looks and feels like Paris, but the added space means things won’t feel cramped while you run across the city’s rooftops. It’s just a matter of adjusting the scale.

And those rooftops provided their own set of challenges. “The skyline of the city was key to me,” says art director Mohamed Gambouz, who wanted to maintain the pointy medieval rooftops and plentiful chimneys that helped define Paris at the time. The problem was that those roofs were a pain to move around on. Previous Assassin’s Creed games featured cities with primarily flat, or slightly slanted rooftops, that made bounding across the city a joy — throw in a bunch of high, pointy roofs and you break up that flow. The solution was to lessen the number of pointy buildings, and make the slants a bit less harsh, so it still looks like Paris but still plays like Assassin’s Creed.

Assassin’s Creed Unity
Assassin’s Creed Unity
The Bastille

It’s just one of many changes made to make ACU’s Paris not only work better for a game, but also match the vision of Paris that players have in their mind. Gambouz calls it the “postcard” effect. “When people talk about Paris they have postcards in their mind,” he says, “even if this postcard isn’t accurate or truthful to the setting.”

In the case of the Notre Dame, easily the biggest structure in the game, it meant recreating a version of the cathedral that didn’t actually exist at the time. Level artist Miousse spent literally years fussing over the details of the building. She pored over photos to get the architecture just right, and worked with texture artists to make sure that each brick was as it should be. She even had historians help her figure out the exact paintings that were hanging on the walls. But when testers started running around the game, something was missing. During the time ACU is set, the Notre Dame didn’t yet have its iconic spires, yet most people picture them when they think about the landmark — so Miousse added them to her creation, even if they technically shouldn’t be there.

Assassin’s Creed Unity
Assassin’s Creed Unity
Assassin’s Creed Unity


The same goes for the Bastille, a Parisian fortress that was destroyed several years before the events of ACU. But because it was such an iconic landmark, the team decided to include it in this version of Paris anyways. They may not be accurate, but these features make the city seem more realistic to the vast majority of players. “The aim is not to be 100 percent historically accurate,” says Gambouz. “It’s to convey a believable setting, a believable city. And sometimes we even go for the perception people have, even if it’s not 100 percent accurate.”

For the development team, Paris also proved to be a challenge to recreate primarily because there was too much of it. “Let’s compare Paris to New York or Boston in the American Revolution (the setting of Assassin’s Creed III), where we had to dig up a lot of information because most of it has been destroyed and it’s really hard to find,” says Ubisoft historian Maxime Durand. “You have just a couple landmarks, and you’re like ‘now we have to make something cool with this.’ For Paris, the challenge is the inverse — everything is interesting, and you have to decide what to cut.”

Designers and artists do much of their own research, using the web and other readily available resources, but Durand and the other historians on the team are there to help find those other, smaller details that really help make the city feel like a real place. That includes everything from the paintings hanging in a cathedral to the clothing worn by peasants in the streets. “We do a tremendous amount of work on small details that people will never notice,” Durand. And those details help offset the creative liberties the designers take with other aspects of the city. “It’s a balance.”

That level of detail is readily apparent when you play. While ACU looks much like every other Assassin’s Creed game at a glance, there’s an extra layer that makes it feel much more realistic. And it’s not just that the graphics are better, it’s also the sense of scale and depth; there’s the way the streets are absolutely bustling with people, all of whom look distinct, or the way you can seamlessly run from a rooftop, through a window, and into someone’s home. Hopping from one building to the next while a gentle sun filters through nearby houses does indeed look like a moving postcard. I only spent around 45 minutes with the game but I wanted much more — not to complete a mission or see what happens next in the story, but just to walk around and enjoy the beauty of Paris.

Miousse knew that all of her work on the Notre Dame was worth it when she finally visited Paris and got to see the building in person for the very first time. After spending countless hours rendering the virtual version, seeing the real thing created a sense of deja vu — everything from the basic structure to the tiniest interior details looked the same. When she went inside, she waited until one of the guards wasn’t looking, and she gave the wall a little kiss.

“For me, it was a lot like visiting my home.”