This paper outlines the design and application of a didactic sequence aimed at facilitating primary students' understanding of axial symmetry, utilizing a combination of digital artefacts and paper tasks. We wondered to what extent the designed didactic sequence is able to make primary school students formulate and validate effective programming strategies to construct symmetrical images with respect to an axis and identify the key properties of axial symmetry. Data analysis from a study carried out with fifth-grade students shows a link between the evolution of students' programming strategies and the construction of mathematical knowledge related to the definition of axial symmetry. The digital artefact and the paper tasks were effective in bringing out programming strategies and some of the key properties of axial symmetry. However, the designed didactic sequence was not enough to allow students to identify all properties related to axial symmetry, and a subsequent intervention by the teacher was necessary. The results of the experimentation led us to expand the paper tasks with additional questions for students.