diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index b868e5e9..e561cbe0 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -164,6 +164,8 @@ Upcoming Release
 
 * Fix duplicated years in `add_land_use_constraint_m`.
 
+* Fix type error with `m` option in `cluster_network`.
+
 PyPSA-Eur 0.10.0 (19th February 2024)
 =====================================
 
diff --git a/scripts/cluster_network.py b/scripts/cluster_network.py
index 3f6c9ea2..22fb4176 100644
--- a/scripts/cluster_network.py
+++ b/scripts/cluster_network.py
@@ -471,7 +471,7 @@ if __name__ == "__main__":
     conventional_carriers = set(params.conventional_carriers)
     if snakemake.wildcards.clusters.endswith("m"):
         n_clusters = int(snakemake.wildcards.clusters[:-1])
-        aggregate_carriers = params.conventional_carriers & aggregate_carriers
+        aggregate_carriers = conventional_carriers & aggregate_carriers
     elif snakemake.wildcards.clusters.endswith("c"):
         n_clusters = int(snakemake.wildcards.clusters[:-1])
         aggregate_carriers = aggregate_carriers - conventional_carriers