The two were arrested during the day on Thursday, the source said, the same day thousands of Kurds gathered in Turkey's southeastern city of Diyarbakir
for the funerals of the three activists.
The source provided no details on the reasons the two people were detained or what role, if any, they are suspected of having played in the killings.
The three women, one of them 55-year-old Sakine Cansiz, a co-founder of the outlawed Kurdistan Workers' Party (PKK), were found shot execution-style at a Kurdish centre in Paris on January 10.
The Paris killings came amid nascent peace talks between Turkish secret services and jailed PKK leader Abdullah Ocalan with the aim of disarming the group, branded as a terrorist organisation by Turkey and much of the international community.
The PKK took up arms for self-rule in the Kurdish-majority southeast in a conflict that has claimed 45,000 lives, mostly Kurds.
Turkish Prime Minister Recep Tayyip Erdogan has speculated the killings could be the result of an "internal feud" within the PKK aimed at sabotaging the talks, recalling that the separatist group has carried out similar
executions in the past.