"Searching for the Grand Paris" "What risks could a Grand Paris based on a smart city model face?" -Beyond the smart city marketing concept, the space of digital in the governance of cities is a real issue to address, as well as in the democratization of this governance, in the citizen's involvement in the city's public policies, etc. Important questions must be raised. We see operators in front of a wall of screens. There is also this image of the control room Salvador Allende built in Chile in 1971 as part of a major cybernetic project meant to collect a lot of information on the economy. In this technologization of the city's governance, there is an underlying risk: private interests can interfere even more in the implementation of the city's public policies because they have the required technical expertise. They are the ones selling those tools, they create the need for these or they lure us with the possible applications when incorporating information technologies in the urban network. Beyond the risk of giving the promise of a technocratic utopia, there are concrete effects in terms of governance that can also raise democratic issues. I see this evolution, this headlong rush towards integrating connected computing, networks, within urban governance as a very important source of weakness for the cities. I am often told that it is a way to be involved in the cities' ecological transition, a way to reinforce their resilience to address socio-economic and ecological issues. Actually, I think that the fact that modern societies and contemporary cities rely more and more on information technologies introduces weak points. For instance, when we connect the transportation systems together, energy and food supply networks, when they depend on digital tools, the slightest perturbation in these technologies, such as cyberattacks or natural disasters, creates a major malfunction risk. In this technocratic utopia I mentioned, and this kind of almightiness implied by the sophistication of our technical tools, we tend to undervalue the weakness induced by their use. There is also something else to mention. We talk about the interest of digital technologies for the cities' ecological transition, without really keeping in mind the major concrete and ecological impact of today's digital infrastructure. In France, it represents about 13% of the country's energy consumption. It represents 9 nuclear plants without mentioning rare metals and the mining it requires to manufacture microprocessors. Computer science has reached a stage where we are ready to computerize our whole concrete environment. In the smart city projects, it is a strong trend. There is the belief that sensors installed in the urban environment will feed these new governance systems with data. The ecological impact of the digital infrastructures is shooting up. This should raise issues or at least become a matter of debate. But once again, it is hidden behind the marketing speech showcased: "Digital is a way to solve ecological issues." But it is also part of the issue and we tend to forget it. Regarding a security aspect, we already face issues with the Internet and the fact that our communication data are traced and collected by different kinds of public or private actors and the kind of surveillance and social control it can imply. Cities are on the verge of becoming digital and multiplying the types of data, not only related to our communications when we use our communication tools such as phones or computers. This computerization penetrates the whole concrete urban environment, in which we move around. It is already true with smartphones. I believe that in terms of surveillance, there is a change of scale that should also raise issues and make us think about the consequences on our life privacy and political relationships in this digital era. I suppose the life privacy issue is taken into account and discussed. But once again, the story of Internet can help us to be more cautious. We must remember that the computerization of societies, at the beginning of the 1970s, when the major public and private bureaucracies were equipped with computers, it created major scandals related to the fear of surveillance. Today, we tend to forget it. It was quite similar to the current debate. At that time, the legal framework to protect personal data, especially the creation of the Cnil in France, arose from these scandals, from these controversaries. But today, the right for personal data, even though it is a useful and necessary legal weapon to fight against this headlong rush to collect and process the data given by Internet users, or more generally speaking in any computer-related situation, is not enough. Because of the speed of innovation, the mass arrival of new applications, new practices in terms of personal data collection and processing, regulators such as the Cnil and we, as citizens, are often defenseless or trying to catch up with the newest practices. So, it is a necessary legal protection that might be too weak. We try to overcome the deficiencies of the law by choosing technical solutions such as the end-to-end encryption of our communications, the use of free software, the control of our personal data that partly goes through free software but also by controlling where our data is hosted, etc. All of this seems to be difficult to implement in the smart city projects. We are already striving to guarantee our life privacy on the Internet even though the solutions seem to be more obvious to implement. The translation of these issues in the smart city framework seems to lead to a greater inability for our societies to really take these issues into account and find appropriate solutions. We can imagine rules, principles, that should lead to a thoughtful and liberating use of the digital in the urban governance systems. According to me, several principles must preside over these developments. First, make sure that the technological solutions used, based on digital tools, do meet actual needs of the population, instead of private companies anticipating these needs. This kind of reform must be anchored in the inhabitants' issue related to economic, social, political issues and democratic involvement governance. Regarding the life privacy of the data generated by these technical systems, there are essential principles. I underlined the risks, but there are essential principles to keep in mind if we head towards this kind of solutions. First, data must be anonymized. Knowing that it will not be enough since individuals can be surveyed and traced even with anonymized data. But it is a basic principle. Globally, everything we call privacy by design: including life privacy when the tools are designed. This will be true for all the solutions we will implement, including cooperative solutions I previously mentioned. The use of free software and transparent algorithms. It goes together. Free software is transparent code open to everyone. And the harmony of algorithms too because we can imagine that in these urban governance systems, they will probably play a role in flow regulation, no matter the objects considered. This is also a very important principle that must be guaranteed.