BERLIN — France and Germany recently issued a joint postage stamp as part of a yearlong celebration of the 50th anniversary of the Élysée Treaty, the landmark agreement between the two former enemies.

The stamp is identical, except for one telling difference. In each country, it bears a picture of a man and woman, side by side, peering through lenses colored in blue-white-red and black-red-gold. But the French stamp costs 80 euro cents, while its German twin sells for only 75.

In a year loaded with symbolic gestures and 4,000 commemorative events, including Tuesday’s joint session of Parliament, joint cabinet dinner and a concert, that 5-cent disparity is a reminder that despite the decades of friendship and enormous day-to-day cooperation, significant, often devilish, differences persist.

De Gaulle once described Europe as “a coach with horses, with Germany the horse and France the coachman.” Since he signed the treaty with the German chancellor Konrad Adenauer in 1963, successive governments in both countries have struggled to overcome, or overlook, what divides them.