One of Zygmunt Mycielski’s closest friends. The two men met before the war in Paris. Czapski and his sister Maria visited Wiśniowa before the war. After the war Mycielski often visited Józio (as he used to call Czapski) in Maisons-Laffitte, where Czapski lived, taking part in the creation of the Paris Kultura. The friendship of Czapski and Mycielski is also documented by thousands of letter exchanged regularly for many years. Czapski is said to have constantly carried some of them on him. After one of his visits to Paris, in May 1967 Mycielski wrote in his diary:

Meetings with Józio always become embedded deeply in my heart, they have substance. With time so many similarities emerge between us and our fates. 

And in 1986 Czapski noted, thinking about Zygmunt Mycielski:

[...] his friendship for me, without a gesture of affection or a superlative, the attitude to me like to his other self. Everything that matters and that used to matter is known to us, so much so that words are unnecessary.