I filled my tax for 2016 in the US and I also had to pay tax in Germany for 2016. How can I deduct these tax in the US because I paid "double" tax now? Thanks!

could you elaborate a little about your status (visa, citizen), where you lived in 20-16, what type of income etc.

I lived in New York in 2016. (I moved to the US in 2015 because I won my greencard in DV Lottery). I had a consulting job in Germany in the first month of 2016 and I fullfiled it from New York. The income in Germany is a self-employed income. In New York I was self employed, too and I worked under a IRS 1099 Form.
In Germany I paid tax (after filing in the US) for my revenue in Gemany. They added the income from the US and calculated the income tax rate. This income tax rate (for both incomes) was applicated to the german income.
In the US I paid the tax on IRS 1099 and on the german revenue.
In Germany I was told, that the tax I paid in Germany will be credited.

I hope I could explain in more or less clear for you. Thanks for helping.

Next time, ask first, then file tax return.

If you are qualified, you can file an amended return to show the tax paid to Germany. You can get a credit for all or some of that tax on your US tax and get a refund. See Form 2555 available at www.irs.gov.
If you can't figure it out you will need to find a professional to assist you.

form 2555 might not apply in this case

First, you need to probably correct your German tax return. Germany does not tax worldwide income if you live abroad. Why did Germany tax that income? Did you pay social security in Germany on that income?

The income you earned for the one month consultant work for a German company is not considered foreign income in the US since you did the work in the US. It is treated just like any other self employment income on a1099.