Should debt be viewed as a major threat to sovereignty, rather than a risk-free guarantee of independence, even for States like France? The development of a public “market debt” has increased the risks to the sovereignty of many countries, including industrialised. The costs of public debt can weaken Governments in several ways, even though some protections may exist. Other risks for sovereignty may arise from the increasing dissemination of the thinking of financial actors on State’s financial strategies and technics.