Prohibitionist policies, as we will see, encourage violence, crime and corruption in the drug market as a result of the fact that illegality gives to these markets economic importance. In order to understand this situation, economy on one side and crime on the other first, we need to realise the economic scale of drug market. What is the economic reality of this market today? A few years ago, in 2005, UN stated of a global market corresponding to 325 billions of US dollars. Let's take methodological precautions as it is still difficult to observe underground markets and derive reliable estimates. Rather than a global number we will prefer national estimates. On this board I give you some recent estimates, as for instance estimates about the Italian drug market: cannabis, cocaine and heroine, where, in 2014 Giommoni evaluate as an example the Italian cannabis market around 550 million of euros for a consumed volume which had been purchased a little less than 70 tonnes. Also recently, in 2016, with some colleagues we evaluated that the cannabis market in France was equal to more than a billion euros for 154 tonnes consumed, still as an example, the cocaine market was equal to 900 millions of euros for 15 tonnes consumed. On this board you can observe that the American market is disproportionate with other countries. Of course there is the impact of the population of users but the more recent American estimates showed that the cannabis market was equal to 41 billion dollars for 5 700 tonnes consumed. The American cocaine market would equal 28 billion dollars in terms of turnover for 145 tonnes of consumed cocaine. As we can see, drug market or at least the turnover made from one country to another is different according to substances and to countries. We can also observe that given the volume of consumed and bought quantities the impact of customs seizures must be quite low. We have a quite important market that produces a quite significant turnover, but we can also observe that the distribution of the profits generated are totally uneven. Particularly upstream and downstream this market, in other words for the farmer and the client. For instance, Wilson and Stevens observed in 2008 that the price for one kilo of cocaine and one of heroine is respectively of 325 pounds and 450 pounds. From the moment we go to international dealers, South-American or Caribbeans for cocaine and Turk for heroine, we witness an increase of the price per kilo of the substance which reach 7 800 pounds for cocaine and 8 000 pounds for heroine, and so on, drugs coming in the British market know another increase, and it is increased once more until the final selling price to the customer or to the street price. These increases from the farmer to the customer are disproportionate if we compare the illicit field to the legal field. As an example, Wilson and Stevens again tell us there is an increase of more than 15 000% for the price of cocaine and of more than 16 000% and even 17 000% for the heroine one. By contrast, if we look at another stimulant such as coffee for instance we have an increase of 400% between the farmer and the final customer so it is clear here that the illicit aspect, the prohibition, encourages profit out of these substances. It is clear that we are on a totally uneven distribution, that the distribution chain is exploited upstream and downstream, on one side the farmer and on the other the dealer. These two individuals have to finally arbitrate between legal and illegal field of work, and the socio-economic conditions, whether upstream or downstream certainly benefits to this illegal work. What is the relationship between prohibitionist policies which encourage this economic gain and crime, violence and corruption? Already 20 years ago in 1995, authors Myron and Svebel showed in a famous paper that the more law enforcement increases the more, on these very markets, the benefit to use violence increases, as it is easier to use murder, torture, violence than a war on prices or a war over the quality of products for instance. Moreover, for these traffickers or these dealers, the cost to use violence will decrease as once I have committed one murder to commit a second, a third or a fourth will not change much to my situation. On an other hand we also notice that repression when it is acting in a framework of competition for space as can be points of sale in a city for instance, will encourage the "balloon effect". Here the balloon effect means that increasing repression on a sale point or on a street or on a neighbourhood for instance will lead to an increase of crime and violence in adjacent areas, as the people who cannot work anymore in an area will move, this relocation will lead traffickers, dealers to fight with each other, and crime will explode. This "balloon effect" phenomenon has been observed at the street and neighbourhood level but also at the city and country level. Finally, the main idea of this "balloon effect" is that the fight against trafficking in a place will only move the problem or even aggravate it. Finally, illegality also encourages corruption. As we can see, the international trade is huge, we go from South America to Europe, from South America to the States of North America and eventually this international trade, through the African routes for instance, benefits currently from the weakness of States institutions. Especially since the cost of this corruption is altogether quite low and that anyway it will be pass on the final selling price. Therefore, by encouraging corruption the illegality of the market discredit and unsettle the institutions democratic and political. It is also clear that these generated sums of money encourage violence, discredit our institutions also, but potentially create negative externalities on the financial and banking system, or even tax havens as all this money needs to be laundered. Laundered at the local level if we look at the bottom of distribution with basic means of laundering, but with way more complex means using the financial and banking system and tax havens on top of the pyramid of profits. We can say that prohibitionist policies by refusing to implement a legal framework of economic competition with tools such as the price, quantities, the quality of products and the use of legal contracts, is only encouraging criminal competition which uses tools such as violence, corruption and the law of the strongest.