The French army had surrendered on 1 September, and on 19 September the German army began to blockade Paris. Lie fled again to Italy, then from there he made his way back to Christiania via Germany so that he could meet and discuss mathematics with Klein .
Ang French hukbo had surrendered on September 1, at sa Setyembre 19 ng German hukbo ay nagsimulang bumangkulong Paris. Tumihaya fled muli sa Italya, at pagkatapos, mula sa may ginawa niya sa kanyang paraan bumalik sa Christiania sa pamamagitan ng Germany kaya na siya ay matugunan at pag-usapan ang matematika sa Klein.