This article examines police-social work partnerships in addressing domestic violence through the embedded social worker type of arrangement in France and Finland. Using comparative analysis, we explore how organizational and institutional factors promote effective collaboration, focusing on trust-building and information exchange. Our findings from qualitative interviews and document analysis indicate that successful collaboration hinges on formal organizational structures that support operations while ensuring professional autonomy. Such conditions foster mutual trust, crucial for sharing sensitive information without breaching confidentiality or ethical norms. We find that excessive oversight leads to mistrust and information withholding. Additionally, our analysis reveals that the effectiveness of these collaborations varies by national context due to differing public pressures and policy priorities. In France, increased attention to domestic violence has paradoxically weakened partnerships by curtailing social workers' autonomy. In Finland, with less emphasis on domestic violence, these issues have become a lower priority, altering the focus of collaboration.