diff --git a/src/operator/Concat.cpp b/src/operator/Concat.cpp
index bf4bbb85be606fc857bf8d771b9ce211ca8e858e..607986e84312413fc10db026c1d8461310237de7 100644
--- a/src/operator/Concat.cpp
+++ b/src/operator/Concat.cpp
@@ -23,7 +23,6 @@ void Aidge::Concat_OpImpl::forward() {
     const DimSize_t axis = op.axis();
 
     assert(op.getInput(0) && "missing input in Concat operator");
-    DataType datatypeFirstInput = op.getInput(0)->dataType();
     for (IOIndex_t i = 1; i < mOp.nbInputs(); ++i) {
         assert(op.getInput(i) && "missing input in Concat operator");
         assert(op.getInput(i)->dataType() == datatypeFirstInput);