The number of international prison standards has risen steadily during the last decades. More than 20 international instruments now stipulate how to enforce prison discipline. Said instruments should ensure that prison conditions are humane and promote good prison management. Safety, security and discipline in prison require, inter alia, dynamic, alert and trained prison staff, pro-active prison directors and room for conflict resolution mechanisms. Compliance with international standards on prison discipline has been researched in Belgium and France, in law and in practice. The research findings are based on an analysis of legal instruments, policy documents and jurisprudence. These findings are complemented with an empirical research in seven prisons in Belgium and France. Data was gathered using methodological triangulation, mostly by studying prison disciplinary files, attending disciplinary hearings and interviewing detainees, prison officers and prison governors. The presentation highlights major deficiencies with prison discipline in both countries, including the lack of information to prisoners on the prison rules, the lack of alternative dispute resolution mechanisms, problems regarding the rules on fact-finding and the burden of proof, and poor detention conditions in solitary confinement. The results are striking as both countries have been through a major legislative reform in 2005.