More recently, the prolonged grief disorder (PGD) has been recognized as a mental health disorder following bereavement, which is distinct from depression and PTSD. However, the number and proposed symptom items vary across the ICD‐11 and the DSM‐5‐TR criteria for PG. The Traumatic Grief Inventory‐Self Report Plus (TGI‐SR+), which is an updated version of the TGI‐SR, is currently the only robust instrument that assesses PG according to the ICD‐11 and DSM‐5‐TR criteria. For research and clinical use among French‐speaking countries, the forward‐backward procedure was applied to translate the TGI‐SR+ into French language. Exploratory factor analysis and parallel analysis converged towards a two‐dimensional structure for the TGI‐SR+, representing adaptation difficulties and traumatic separation distress. However, items mapping onto ICD‐11 and DSM‐5‐TR criteria for PG represented a one‐dimensional structure. Findings based on item response theory method provided strong evidence for discriminative characteristics of the items. The internal reliability was excellent for the TGI‐SR+ (McDonald's ω = 0.97) and ICD‐11 and DSM‐5‐TR criteria for PGD (McDonald's ω = 0.95). We also demonstrated a very high temporal stability for the TGI‐SR+ total score (ICC = .91, p < 0.0001) and ICD‐11 PGD and DSM‐5‐TR PGD (ICC = 0.90, and ICC = 0.88, ps < 0.0001, respectively). The concurrent validity of the instrument was also demonstrated, such that the TGI‐SR+ total score and all combinations were positively and significantly associated with the levels of depression, anxiety and post‐traumatic stress symptoms. However, the effect sizes were moderate. We conclude that for research and clinical use among French bereaved populations, the TGI‐SR+ is a sound tool with very good psychometric properties.