Can't insert data in the same previous form - I lose data when I create a new form

Question

My problem is that when I choose a row in my datagridview, it opens a new form, not the previous one.

Here is my code:

Button: "choix de l'article" in "Form1" : f2 to call form2

public partial class A_commande : Form
{
    public A_commande()
    {
        InitializeComponent();
    }

    private void button12_Click(object sender, EventArgs e)
    {
        A_fournisseur_article f2 = new A_fournisseur_article();

        f2.Show();
    }
}

Form2: f1 to call form1

private void articleDataGridView_CellMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
{
        if (e.RowIndex >= 0)
        {
            A_commande f1 = new A_commande();
            DataGridViewRow row = this.articleDataGridView.Rows[e.RowIndex];

            f1.articleComboBox.Text = articleDataGridView.CurrentRow.Cells[0].Value.ToString();
            f1.catégorieTextBox.Text = articleDataGridView.CurrentRow.Cells[1].Value.ToString();

            this.Hide();
            f1.Show();
        }
}

Form1

Form2

(My problem): it's not "form1" but I get "new form1"

Thank you so much for your time.