Purpose The purpose of this paper is to examine the relationship between leverage and firm performance using small business data from France by estimating the effects of leverage on both average firm performance and the variance of firm performance. Design/methodology/approach Focusing on French small- and medium-sized enterprises (SMEs), which tend to be dependent on bank loans, the authors examine the relationship between leverage and firm performance. This study was based on a unique panel data set of more than 2,157 manufacturing SMEs covering the years 2007-2015. The authors estimate the effects of leverage on both average firm performance and the variance of firm performance. Findings Focusing on the average effects of leverage, the authors find that highly leveraged firms suffer from poor performance. In addition, the variance in firm performance is higher if firms are highly leveraged. Results also underline that leveraged firms are better performers when they have sufficient collateral assets. Research limitations/implications The study, however, has also some limitations. The first one is that the findings were obtained for only one industry sector, so attempts should be made to study the issue, as it applies to other sectors as well. Second is the context where the study was conducted. This study has been conducted based on data gathered from SMEs in France within a specific socioeconomic context (2007-2008 global financial crisis), which may also limit the generalizability of the results for different contexts with different socioeconomic situations. It would also be useful, to have a better explanation for the performance of SMEs, to add to the model more financial variables or other types of variables such as those related to managerial skills or to the macro-economic environment. Finally, further research could examine the joint impact of both leverage and ownership structure on firm’s performance as a large number of French firms are family firms. The limitations of this study, however, can in fact be an opportunity for future researchers to conduct studies addressing those limitations. Practical implications This research has some implications for small business lending. SME owners and managers may, on the one hand, be encouraged by the fact that collateral assets can reduce agency costs, thereby positively affecting firm performance. On the other hand, high leverage can facilitate firm growth if firms have collateral assets. This implies that policymakers interested in stimulating SMEs should develop more suitable collaterals for high-risk SMEs with low asset tangibility. Social implications The results also have implications for financial institutions. To prevent unexpected and extensive bankruptcies, banks might classify firms with negative cash flows as borrower in danger of bankruptcy. However, the results show that highly leveraged firms with good investment opportunities and high collateral assets reduce the probability of bankruptcy. This implies that banks need to evaluate the credit risk of very highly leveraged small businesses more carefully. Originality/value It should be noted that the case of France remains marginal in terms of the conducted studies.