In its judgment file no. 23 Cdo 1878/2015 on September 6, 2016), the Czech Supreme Court dealt with cases where a claim arising under the previous law (Act no. 40/1964 Coll., the Civil Code) was assigned, and the assignor informed the assignee of this fact after the new law (Act. 89/2012 Coll., the Civil Code, as amended) took effect. According to the court, the effects of that notification will be assessed as legal facts connected with a rights transfer under the Civil Procedure Code doctrine of procedural succession. The questions of whether the claim was truly assigned, and whether this assignment is valid, can only be addressed in litigation between the assignor and assignee. This means that in cases where a debtor is being sued, once this person learns about the claimant (assignor)’s application for procedural succession, the court will not examine the validity or even the existence of an agreement on claim assignment.