Hi, Pierre!
Add a TextFrame to the footer and then add paragraphs to the TextFrame:
Code:
// Create footer
TextFrame textFrame = section.Footers.Primary.AddTextFrame();
textFrame.Width = "17cm";
Paragraph paragraph = textFrame.AddParagraph();
paragraph.AddText("PowerBooks Inc · Sample Street 42 · 56789 Cologne · Germany");
paragraph.Format.Font.Size = 9;
paragraph.Format.Alignment = ParagraphAlignment.Center;
paragraph = textFrame.AddParagraph();
paragraph.AddText("PowerBooks Inc · Sample Street 42 · 56789 Cologne · Germany");
paragraph.Format.Font.Size = 8;
paragraph.Format.Alignment = ParagraphAlignment.Center;
paragraph = textFrame.AddParagraph();
paragraph.AddText("PowerBooks Inc · Sample Street 42 · 56789 Cologne · Germany");
paragraph.Format.Font.Size = 7;
paragraph.Format.Alignment = ParagraphAlignment.Center;