Abstract
The telecommunications sector has becomes very important for today's society, as it allows people at either end of the world to communicate, as well as it contributes to the growth of our productivity. In order to fully benefit from this sector, a deep understanding of its functioning is indispensable.The aim of this thesis is to contribute to its better comprehension by focusing in particular on questions relative to the competition in this sector.This thesis concentrates first on the competition between fixed and mobile telecommunications services. Indeed, contradictory evolutions are observed. First, the number of consumers relying only on their mobile so as to satisfy their need in telecommunications increases steadily. Second, the number of subscriptions of bundled offers, regrouping fixed and mobile services, has also increased in an impressive manner. The question, treated in the first chapter, is thus to know whether the practice of bundling is profitable for telecommunications operators, as well as the impacts on social welfare induced by this strategy.A theoretical model, integrating horizontal differentiation, Fixed-Mobile substitution and heterogeneous consumer preferences, allows to conclude that operators are likely to lose profits when bundling their services, whereas consumers are clear winners. Furthermore, the increase of consumer surplus more than compensates the firms' profit losses, such that social welfare increases.Fixed-Mobile substitution is also at the core of the second chapter. Its aim is to determine the socio-demographic characteristics of about 20.000 French users that explain best the users' choice of subscribing either to only a mobile offer, to a bundled offer or to several services separately.The main result is that “mobile-only” consumers seem to have a stronger budget constraint than “multi-service” users. Moreover, the study provides evidence for an “incumbency advantage” when it comes to subscribing to a bundled offer.The thesis then turns to competition between firms. More specifically, the third and last chapter offers an analysis of the impact on the equilibrium in a network industry induced by the interaction of sector regulation (notably, price regulation) and competition law (notably, the prohibition of the so-called “margin squeeze”). The debate on this subject has induced two widely opposed points of view, in particular between the US and Europe: whereas the US considers both tools to be substitutes, they are used as complements in Europe. The underlying question is thus evident: which doctrine has the least impact on the market efficiency?A theoretical analysis allows first to show that the retail price set by a vertically integrated firm, that owns the physical network and grants its downstream competitor access to it against the payment of an “access charge”, may not comply with competition law without any anticompetitive intention. Moreover, applying competition law in combination with sector regulation (notably, regulation the level of the access charge) leads to market inefficiency, characterized by an increase of retail prices, which is detrimental to consumer surplus and social welfare.The thesis concludes by reminding the importance of a deep understanding of the functioning of the telecommunications sector. Since the evolutions in this sector are not harmless, many theoretical and empirical analyses are need, so that every one can profit from the contribution of this sector.