From The Catholic Encyclopedia, we read the truth about Christian communism in Jerusalem and monastic orders. Please see source footnote.
The communistic principle governed for a time the lives of the first Christians of Jerusalem. In the fourth chapter of the Acts of the Apostles we learn that none of the brethren called anything that he possessed his own; that those who had houses and lands sold them and laid the price at the feet of the Apostles, who distributed "to everyone according as he had need". Inasmuch as they made no distinction between citizens and slaves, these primitive Christians were in advance of the communism of Plato. Their communism was, moreover, entirely voluntary and spontaneous. The words of St. Peter to Ananias prove that individual Christians were quite free to retain their private property. Finally, the arrangement did not long continue, nor was it adopted by any of the other Christian bodies outside of Jerusalem. Hence the assertion that Christianity was in the beginning communistic is a gross exaggeration.Source: New Advent