The article analyzes the dynamics of the financial fragility of French private non-financial firms using the Financial Instability Hypothesis developed by Hyman Philip Minsky. This hypothesis contains analytical tools to explore the relationship between the course of the business cycle and the dynamics of the structure of private firms' financial flows. Our sample includes 208 private sector enterprises in France. The study covers time period from 1998 to 2018. The source of data is the Thomson Reuters platform. Related indicators are considered separately for three categories of companies depending on the size of their revenue -small, medium and large businesses -and for ten categories of companies depending on their industry affiliation. Three criteria are used to classify the companies into hedge firms, firms with speculative financing and Ponzi firms. Our empirical analysis showed that before the onset of the Great Recession in the French economy, the share of Ponzi firms grew, and reached its maximum at the peak of economic hardship. In line with the Financial Instability Hypothesis, the research findings confirm that the accumulation of financial fragility is associated with the onset of the Great Recession in France. It is further shown that small firms are much more financially fragile compared to medium and large businesses, and the real estate sector turned out to be the most financially fragile sector of the French economy.