1. INTRODUCTION
2. OBSERVATIONS
3. RESULTS
3.2. Substructures in the prestellar core G205-M3
4. DISCUSSION
4.1. Detection of compact structures
4.2. Thermal stability
4.3. Dynamical state
4.4. Substructures toward G205-M3 and stellar multiplicity
4.5. Physical explanations for fragmentation
5. SUMMARY