I added the built-in regularizer tf.contrib.layers.l2_regularizer as such:
regularizer = tf.contrib.layers.l2_regularizer(scale=0.1)
layer1 = tf.layers.dense(tf_x, 50, tf.nn.relu, kernel_regularizer=regularizer)
layer2 = tf.layers.dense(layer1, 50, tf.nn.relu, kernel_regularizer=regularizer)
output = tf.layers.dense(layer2, 5, tf.nn.relu)
I tried different values for scale (0.1-1), but it didn't seem to do much. I was wondering whether I have to do add the regularizer at some other position (i.e. optimizer, train etc.) or whether this might simply be due to my data.
I didn't adjust any other position in my code for the regularizer then in the tf.layers like above.