In a small bowl combine yeast with warm water and set aside for 10 minutes till the mixture is foamy.
Meanwhile, in a mixing bowl combine the flour, eggs, sugar and butter; knead into dough. Add the yeast and knead for 10 minutes; cover and let rise for 2 hours in a dark, warm spot.
Preheat oven to 180 C / Gas 4 and lightly grease a 450g (1 lb) loaf tin.
Knead dough again, working in the chocolate chips. Place dough in prepared tin and bake in preheated oven for 30 minutes; let cool and serve at room temperature.