How would you cover a bathroom window on the front of a house?

Home Depot sells privacy window film

You can buy and apply static cling window films. They're an easy DIY project since they're adhesive-free and easy to change if you don't like the effect. Most do allow natural light to enter. Decorative Films is a good online retailer: https://www.decorativefilm.com/static-cling-films

Could you put a cafe curtain on the bottom half of the window leaving the top half uncovered?

Try a self-adhesive 'privacy' film...They often come in a variety of color and textured designs and allow in light.

How about blinds with a valence on top?

I had this problem too. I used a window glass kit to make it look like stained glass. My stained glass was a coyote profile with a moon and tall buttes because our home is decorated western but you could make flowers, or any picture. I used a coloring book for my idea because the lines are simple. The kits are available at Home Depot, Hobby Lobby and other place where you purchase home decor items. I liked the stained glass window idea because it lets light in but still covers the window. Here are a couple simpler geometric ideas. You can use the colors and shapes you prefer or do like me and use an idea from a coloring book. Some kits also come with picture ideas in them. They can also be removed if you want to replace them, change the decoration theme in the bathroom, or just take it down. Here are two geometric ideas:

Opaque window film or a light colored curtain that would provide privacy but still let some naural light through. Or replace the glass in the window itself.

Net Curtain & Blind, or Shutters

Lowes and Home Depot have some great window film, decorative and easy to apply

a sheer with enough pattern to hide the ovcupants, or. Plant a bush!

You could use anything you want to, just open for light when you aren't using the bathroom. I have rollup shades, but they can't be seen from the outside because of two huge shrubs that give us privacy.

Amazon has a large selection of non-adhesive window film in lots of patterns. Or you could get etching cream and etch the glass permanently.

https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=non-adhesive+privacy+window+film

https://www.amazon.com/Armour-Etch-15-0250-Cream-22-Ounce/dp/B000XAN6NA/ref=sr_1_3?ie=UTF8&qid=1502037703&sr=8-3&keywords=etching+cream

I bought and put up this huge decal years ago. It hasn't faded. At least you USE to be able to buy them... I think at Lowes. There are lighter colored ones too. But more variation in colors would give more privacy than the all white ones would.

No tools (except measuring and cutting the decal) needed. You press it on. It can be removed easily too! I only put it on the lower window (as shown) for more natural light to come through. I was able to do bathroom windows with the decal I bought.

There are window cling films you came buy that will do exactly that; create privacy but allow the light to come in. I found mine at Bed Bath & Beyound.