The shade of green you choose for the foyer can range considerably. The shade you choose should accent the "feel" you want you and your guests to experience when crossing the threshold. For example, for something peaceful and inviting, look toward cool, relaxing shades of mint or sage green. For something classic and strong, choose a shade of saturated hunter green or forest green. In a contemporary or tropics-inspired space, be bold with a shade of lime green to make a splashy statement in this greeting area.
Instead of painting the walls one flat shade of green, consider using stencils to frame the foyer. This can give this area the illusion of a faux wallpaper for a fraction of the price and hassle of installing real wallpaper. Consider traditional wallpaper prints for an accent wall in the foyer, from scrolling floral designs or all-over repeating damask shapes. Instead of painting just an accent wall, paint each wall of the foyer for a bold entrance point for you and your guests.
Faux techniques will add texture to ordinary flat paint. For example, sponge green paint into the foyer for a soft addition of color that invites guests without overwhelming the walls. Similar to using a sponge to paint, use a microfiber rag to gently smudge and soften green paint on the walls. While it requires extra time and expense, a Venetian plaster treatment in shades of green is a charming and old world-inspired faux technique for this important entryway area.
The right lighting really improves the color green, especially in the foyer space. If your foyer is bright and naturally lit, you can use darker shades to cover the walls of this area. However, if the lighting is dark, avoid heavy shades of green; they'll just make the entrance feel cramped and cavelike. Sconces in complementing shades or even an overhead chandelier can improve the lighting situation in the foyer and better showcase your chosen shade of green paint.