Very observant. Both 'package' and 'packet' translate into German as 'Packet'.
Aha. Never thought about the etymology before. Here's the entries for the two at my favorite dictionary site:
<http://dictionary.reference.com/search?q=packet>
<http://dictionary.reference.com/search?q=package>
So "package" is something that has been packed, and "packet" is a small package. Does German have something like the English (or is it French?) "ette" suffix for creating diminutives from other words?