diff --git a/src/algebra/TinyMatrix.hpp b/src/algebra/TinyMatrix.hpp
index 1bb3a3a4488819923b81faea28c5d9ff9f649205..027c7c191e2c0174effd9bb2e17ace72c213ae6c 100644
--- a/src/algebra/TinyMatrix.hpp
+++ b/src/algebra/TinyMatrix.hpp
@@ -416,7 +416,8 @@ T cofactor(const TinyMatrix<N,T>& A,
            const size_t& j)
 {
   static_assert(std::is_arithmetic<T>::value, "cofactor is not defined for non arithmetic types");
-  const T sign = ((i+j)%2) ? 1 : -1;
+  const T sign = ((i+j)%2) ? -1 : 1;
+
   return sign * det(getMinor(A, i, j));
 }