How Criteo’s AI Lab is solving real-world advertising challenges

Criteo, a Paris-based ad tech firm, is leveraging artificial intelligence (AI) to transform digital advertising, for both its global and Indian customers. At the heart of this transformation is the company’s AI Lab, headed by Vice President of Engineering Romain Lerallut, which utilises deep learning, machine learning, and real-time data processing to create personalised and effective ad experiences while prioritising privacy and ethical considerations.

In an exclusive interview with TechCircle, Lerallut explained the structure and function of the AI lab and how it is solving real-world problems in advertising.

Inside Criteo’s AI Lab

In 2018, Criteo invested €20 million ($21.2 million) to set up the AI Lab in Paris, a research and engineering hub within its broader research & development (R&D) team that develops the AI and machine learning models that power Criteo’s comprehensive AI engine. 

Lerallut informed that the lab has a dedicated team of 100 AI specialists focused on developing and integrating cutting-edge AI research into Criteo's production systems and contributing to the broader understanding of AI techniques. “Criteo's broader Product and R&D departments include over 1,000 professionals whose work incorporates AI,” he said.

The AI officer explained that Criteo's AI Engine analyses real-time data from 700 million daily active users, billions of SKUs across 3,700 product categories, and over $1 trillion in online transactions to deliver 1.9 trillion ads annually (over 5 billion per day).

On how Criteo's AI-driven engine tackles intricate advertising challenges and creates customised experiences for billions of users, Lerallut said.

“The company uses advanced models like the Deep KNN algorithm (a non-parametric, supervised learning classifier, which uses proximity to make classifications or predictions about the grouping of an individual data point) that enables the engine to provide insights into consumer behaviour, enabling brands to understand how consumers discover, compare, and purchase products”.

“This helps brands better understand how consumers discover, compare, and purchase products—delivering deeper insights into consumer behaviour and more meaningful connections,” he added.

AI ethics and safeguarding data

Criteo follows strict advertising guidelines, with a dedicated product ethics committee composed of experts from legal, engineering, business, and marketing backgrounds. This diverse team meets quarterly to review policies, assess ethical concerns, and recommend adjustments.

“Their role is to ensure that our AI aligns with ethical standards across different cultural and regulatory contexts. By maintaining this structured approach, we can proactively address challenges and continuously improve the fairness and transparency of our AI systems,” said Lerallut.

AI also plays a critical role in safeguarding customer data. According to him, “We leverage Deep KNN to extract valuable insights from vast, complex, and often unlinked datasets—without exposing personal information. By prioritising first-party data and minimising reliance on third-party trackers, we enable privacy-friendly personalisation.”

He further informed that rather than tracking individuals, the company creates pseudonymous audience segments to deliver relevant ads securely and responsibly. “Our use of encryption, anonymisation, and Data Clean Rooms ensures compliance with global regulations such as GDPR and CCPA,” said Lerallut, adding that this technique helps brands build meaningful connections with their audience while upholding the highest standards of privacy and trust.

To foster innovation, the AI Lab also collaborates with academic institutions like Inria and ENSAE through initiatives like FairPlay, a joint research team focused on developing algorithms that learn alongside users. Researchers include PhD students with dual supervision, fostering connections between industry and academia. 

The Criteo AI Lab also hosts the Distinguished Lecture Series (DLS) to share insights and foster innovation. As Lerallut said, the company contributes to the AI community by opening datasets for researchers to use, including FairJob and CriteoPrivateAd, which focus on unbiased recommendations and private advertising techniques.

According to Lerallut, finding the right skill sets is a big challenge and the company seeks candidates with expertise in machine learning, deep learning (neural networks, reinforcement learning, and generative AI), big data processing, and cloud computing. A strong foundation in data privacy, security, and ethical AI is also valued, along with problem-solving, innovation, and teamwork skills.

India’s AI-led ad innovation

Lerallut believes that AI is central to marketing and advertising innovation in India, with marketing leaders investing in generative AI, with many seeing tangible results, as per the company’s latest surveys.  

“AI is also enabling hyper-personalisation at scale. Through data-driven insights and creative automation, brands can now craft experiences tailored to individual needs, preferences, and behaviours. Innovations like AI-powered vernacular chatbots, interactive product discovery tools, and personal AI models are reshaping how brands connect with consumers,” he said.

At Criteo, we’re leading this shift with Commerce GO! Our next-gen AI-powered tool within the Commerce Growth platform. “It simplifies campaign creation to just five clicks, automating decisions across audiences, and channels, and creating and delivering smarter, more personalised ads across the full funnel,” summed up Lerallut.