Laura's star by Klaus Baumgart

When you have a friend you take on new responsibilities. You must listen to your friend and care for them and above all not act in a selfish way towards them.  The back cover says "a lonely girl learns that friendship sometimes means letting go of your most precious treasures."

Laura finds a star on the pavement outside her home one evening.  She has been longing for a friend and the little star seems to be perfect. The star is slightly damaged so she carefully repairs it with a band aid.  By day her star cannot be seen but in the evenings it shines.  Then things begin to go wrong :

"Laura stroked the little star gently with her fingertips as it grew colder still. She felt the longing in it, and suddenly she understood why her little star was dying."

Laura attaches the star to a set of balloons and releases it into the night sky."Laura didn't feel sad any more, for her star was back where it belonged."

This is the first book in a lovely series about Laura and her star. The foil stars are a special feature and after reading Laura's star you might look for the Christmas one.  This book was first published in German and I even found a Greek version.  Here is a gentle little video of the story.