Where in the Catholic Bible is the birth of Jesus Christ?

The same as any version, the account of Jesus birth can be found in Matthew 1:18-2:1 and Luke 2:1-7

The Douay-Rheims Catholic version contains the 'apocryphal' books, and combines the 9th and 10th Psalm, resulting in the remainder of Psalms being out of sync with most translations, but the rest of The Bible is the same as most translations.