Cette thèse se structure en 2 parties, le marché physique et le marché financier des matières premières agricoles et prend 3 thèmes intéressants à étudier. D'une part, si les interventions sur les marchés des matières premières sont limitées, une autre option toujours ouverte est de tenter d'atténuer les impacts négatifs des comportements extrêmes des prix. Ce thème fait le point sur la gestion efficace des risques. D'autre part, à ce jour aucun consensus n'a pu être trouvé concernant l'impact des nouveaux produits dérivés (ex : fonds indiciels). Cette question peut en fait être abordée directement dans l'impact des fonds indiciels sur le stockage des matières premières. Enfin, parmi les régulateurs sur les marchés des matières premières, le rôle des banques centrales est souvent ignoré. Pourtant, elles peuvent aussi être un régulateur efficace sur ces marchés. / This thesis provides an overview on the evolution of commodity markets and focuses on the price behaviour in both the commodity physical and the financial derivatives markets. Instead of directly analysing regulation in the commodity markets, this thesis highlights the market changes and specific market behaviour, which gives potential implications for market regulation.Main results of thesis. This research on regulation of commodity markets has been conducted within two different markets: commodity physical markets and commodity derivatives markets. Results in physical markets confirm the evidence of jump in agricultural commodity prices. Price volatility varies with time and is not constant. Commodity markets’ –at least agricultural markets’- prices oscillated during the period 2007/2008, which coincided with financial crisis. Relatively high frequent and small jumps in commodity prices are probably due to financial market factors instead of market fundamentals.The implication of these results in risk management of agricultural cooperatives is that, although taking into account jump in risk measure, such as VaR does not out-perform traditional VaR with normal distribution. Considering this kind of extreme price variation can be complementary for risk managers when facing a highly volatile commodity market. Findings for financial derivatives markets lead to two conclusions.Firstly, commodity index funds are confirmed again as having a short-term impact on futures prices in most products. Based on the theoretical conclusion about the intermediary role of inventory on the impact of speculation on the commodity market, we have found that commodity index can influence commodity futures prices without necessarily passing through inventory changes, which is probably due to price-inelasticity. Secondly, in relation to the impact of central bank announcements on commodity prices, the study shows that the central bank can be an alternative regulator to influence the commodity market. Additionally, it shows that commodity prices include the information from macroeconomic factors, such as currency rate and inflation rate.