This is something I have been researching a lot, so here's my thoughts for what they're worth
Understanding sunscreens and their effectiveness is hugely complicated, there's many different options, regulations and standards. Firstly, with skincare, what works for one doesn't work for another so this is something which is trial & error - learning what ingredients work for you and your lifestyle. So take into consideration your location, your skin & your needs. I do believe we should all take necessary precautions during hot weather, so avoid the sun at peak hours, use sunglasses and hat, reapply sunscreen after sweating or swimming. Regardless of where you live, UV rays are present but you can modify the protection for your location. I'm in the UK, so for most of the year I'm not in intense sunshine, but I'll always use a high PPD sunscreen to help against UVA. If you use exfoliants, you will need protection. I use Avene Diacneal (retinaldehyde and glycolic acid) therefore the new skin cells being exposed need protection to avoid repeating the skin darkening (acne scarring) I'm trying to prevent. The other thing that is important to remember is the amount you're using. The rating on your product (let's say it's SPF 15) is based on 1/4 teaspoon amount for face. If you do not use that amount, you are only getting a fraction of the protection, and this is where it gets difficult to wear under makeup.
Physical sunscreens (these are best for blocking UVB (burning) rays and offer a minimal UVA protection - maybe PPD 8-10 max) are good for those with sensitive skin, in particular zinc oxide. These do not degrade in sunlight and therefore do not need to be reapplied as often. They can however be chalky, thick and whitening.
Chemical sunscreens are often more cosmetically elegant formulations, however many like Avobenzone degrade under light. They offer superior protection for long wave UVA rays meaning they are better for those concerned about aging & cancer. Mexoryl SX (found in LRP and L'Oreal) is more stable but I believe does not offer quite as good protection. Tinosorbs M & S offer the most protection.
Avobenzone doesn't play well with mineral sunscreens - in any case, it must be stablized itself (usually by octocrylene). If the minerals are coated, it's better but this is not always the case. What is important to note here is, most makeup contains titanium dioxide even if it is marketed as not containing an SPF. Therefore you risk compromising your protection if you do not understand the ingredients you are combining. In any case, sunscreens are not tested with foundation on top so I believe that putting anything on top affects its performance. Also, protection cannot be layered - SPF 15 moisturiser and SPF 15 foundation do not SPF 30 make. I try to use only products without SPF so that I am in control of the ingredients and protection.
So I guess this probably doesn't help you find a good sunscreen to wear under makeup. My advice...do the best you can. Protect yourself by being sensible about your exposure. Find the sunscreen that sits nicely on your skin and then you will want to wear it. Learn about ingredients to find out what suits your skin and your needs. Don't be afraid of the sun but be very aware of its dangers, both for your appearance and your health. Many people wonder about how safe it is to be using sunscreen daily. Certainly there are major health problems associated with a lack of vitamin D, but my approach is: sunscreens may pose a problem & if something is absolutely proved to be unsafe and removed from the market, I would not use it. The sun is a known danger, at best you will age rapidly and at worst you may die from skin cancer. My preference is for European sunscreens & I would not use Oxybenzone. Many European formulations offer moisturisers now with high PPD (Vichy Aqualia Thermal has one with PPD 18) which is a nice alternative, particularly for those with dry skin because you need to use the correct amount. Also, whilst mixing foundation with sunscreen is a no-no because it dilutes the protection, you can buy tinted sunscreens to add into your regular sunscreen.
You shouldn't be afraid of the sun, just be sensible
YAY! Is it a danish brand? I have been meaning to throw out my unused SPF50 creams for a long, long time. I was an idiot to get them in the first place. 
), and I've never had a sunburn in my entire life. I'm very fair, but I don't need more than SPF 20. Very few people do, really.
I'm not an expert, but I would rather trust what the medical schools say than the companies claim...
is it available in germany?
